(DOCSP-39514): Consolidate Read page (#3357)

## Pull Request Info - SDK Docs Consolidation

Jira ticket: https://jira.mongodb.org/browse/DOCSP-39514

*Staged Page*

-
[Read](https://preview-mongodbdacharyc.gatsbyjs.io/realm/DOCSP-39514/sdk/crud/read/)
- [Read
Properties](https://preview-mongodbdacharyc.gatsbyjs.io/realm/DOCSP-39514/sdk/crud/read/read-properties/)
- [Fluent Interface (Java
SDK)](https://preview-mongodbdacharyc.gatsbyjs.io/realm/DOCSP-39514/sdk/crud/query-engines/filter-data-java-sdk/):
Port content, update Realm naming, and change to use the Drivers tab
languages so it preserves a language selection when clicking into the
page
- [LINQ (.NET
SDK)](https://preview-mongodbdacharyc.gatsbyjs.io/realm/DOCSP-39514/sdk/crud/query-engines/filter-data-linq/):
Port LINQ content, update Realm naming, omit stuff about querying with
RQL as that is generally surfaced in the C# API descriptions on the Read
page

*Page Source*

Add links to every SDK's pages where you got the SDK-specific
information:

- [C++:
Read](https://www.mongodb.com/docs/atlas/device-sdks/sdk/cpp/crud/read/)
- [Flutter:
Read](https://www.mongodb.com/docs/atlas/device-sdks/sdk/flutter/crud/read/)
- [Flutter: Model
Data/Results](https://www.mongodb.com/docs/atlas/device-sdks/sdk/flutter/realm-database/model-data/data-types/#realmresults)
- [Flutter: Model Data/Geospatial
Data](https://www.mongodb.com/docs/atlas/device-sdks/sdk/flutter/realm-database/model-data/geospatial/)
- [Java:
Read](https://www.mongodb.com/docs/atlas/device-sdks/sdk/java/crud/read/)
- [Java: Filter
Data](https://www.mongodb.com/docs/atlas/device-sdks/sdk/java/crud/filter-data/)
- [Java: Model
Data/Results](https://www.mongodb.com/docs/atlas/device-sdks/sdk/java/model-data/data-types/collections/#results-collections)
- [Java: Data Types/Mixed
(Queries)](https://www.mongodb.com/docs/atlas/device-sdks/sdk/java/model-data/data-types/realmany/#queries)
- [Kotlin:
Read](https://www.mongodb.com/docs/atlas/device-sdks/sdk/kotlin/realm-database/crud/read/)
- [Kotlin: Model Data/Geospatial
Data](https://www.mongodb.com/docs/atlas/device-sdks/sdk/kotlin/realm-database/schemas/geospatials/)
- [.NET:
Read](https://www.mongodb.com/docs/atlas/device-sdks/sdk/dotnet/crud/read/)
- [.NET: Filter
Data](https://www.mongodb.com/docs/atlas/device-sdks/sdk/dotnet/crud/filter/)
- [.NET: Results
Collections](https://www.mongodb.com/docs/atlas/device-sdks/sdk/dotnet/model-data/data-types/collections/)
- [.NET: Geospatial
Data](https://www.mongodb.com/docs/atlas/device-sdks/sdk/dotnet/model-data/data-types/geospatials/)
- [Node.js:
Read](https://www.mongodb.com/docs/atlas/device-sdks/sdk/node/crud/read/)
- [Node.js: Collections (info about
Results)](https://www.mongodb.com/docs/atlas/device-sdks/sdk/node/model-data/data-types/collections/)
- [Node.js: Relationships (Inverse relationship
info](https://www.mongodb.com/docs/atlas/device-sdks/sdk/node/model-data/relationships-and-embedded-objects/)
- [Node.js: Data Types/Dictionaries
(Query)](https://www.mongodb.com/docs/atlas/device-sdks/sdk/node/model-data/data-types/dictionaries/#query-for-objects-with-a-dictionary-property)
- [Node.js: Data Types/Sets (info relevant to reading set
properties)](https://www.mongodb.com/docs/atlas/device-sdks/sdk/node/model-data/data-types/sets/)
- [Node.js: Data Types/Mixed
(Query)](https://www.mongodb.com/docs/atlas/device-sdks/sdk/node/model-data/data-types/mixed/#query-for-objects-with-a-mixed-value)
- [Node.js: Data Types/Geospatial
(Query)](https://www.mongodb.com/docs/atlas/device-sdks/sdk/node/model-data/data-types/geospatial/#query-geospatial-data)
- [Swift:
Read](https://www.mongodb.com/docs/atlas/device-sdks/sdk/swift/crud/read/)
- [Swift: Supported Types: Results & Sectioned
Results](https://www.mongodb.com/docs/atlas/device-sdks/sdk/swift/model-data/supported-types/#results-and-sectioned-results)

### PR Author Checklist

Before requesting a review for your PR, please check these items:

- [x] Open the PR against the `feature-consolidated-sdk-docs` branch
instead of `master`
- [x] Tag the consolidated page for:
  - genre
  - meta.keywords
  - meta.description

#### Naming
- [x] Update Realm naming and the language around persistence
layer/local/device per [this
document](https://docs.google.com/document/d/126OczVxBWAwZ4P5ZsSM29WI3REvONEr1ald-mAwPtyQ/edit?usp=sharing)
- [x] Include `.rst` files comply with [the naming
guidelines](https://docs.google.com/document/d/1h8cr66zoEVeXytVfvDxlCSsUS5IZwvUQvfSCEXNMpek/edit#heading=h.ulh8b5f2hu9)

#### Links and Refs
- [x] Create new consolidated SDK ref targets starting with "_sdks-" for
relevant sections
- [x] Remove or update any SDK-specific refs to use the new consolidated
SDK ref targets
- [x] [Update any Kotlin API
links](https://jira.mongodb.org/browse/DOCSP-32519) to use the new
Kotlin SDK roles

#### Content
- [x] Shared code boxes have snippets or placeholders for all 9
languages
- [x] API description sections have API details or a generic placeholder
for all 9 languages
- [x] Check related pages for relevant content to include
- [x] Create a ticket for missing examples in each relevant SDK:
Consolidation Gaps epic

### Reviewer Checklist

As a reviewer, please check these items:

- [ ] Shared code example boxes contain language-specific snippets or
placeholders for every language
- [ ] API reference details contain working API reference links or
generic content
- [ ] Realm naming/language has been updated
- [ ] All relevant content from individual SDK pages is present on the
consolidated page

Author: dacharyc

snooty.toml

@@ -11,6 +11,7 @@ intersphinx = [
 toc_landing_pages = [
   # New IA
   "/sdk/crud/create",
+  "/sdk/crud/read",
   "/sdk/platforms/android",
   "/sdk/platforms/apple",
   "/sdk/platforms/unity",

source/includes/api-details/cpp/crud/read-access-results-description.rst

@@ -0,0 +1,7 @@
+In C++, the :cpp-sdk:`Results <structrealm_1_1results.html>` type exposes member 
+functions to work with results. You may want to check the ``.size()`` of a
+results set, or access the object at a specific index.
+
+Additionally, you can iterate through the results, or observe a results
+set for changes. For more details about observing the results for changes,
+refer to :ref:`sdks-react-to-changes`.

source/includes/api-details/cpp/crud/read-aggregate-not-supported.rst

@@ -0,0 +1 @@
+C++ does not currently support aggregate operators.

source/includes/api-details/cpp/crud/read-all-objects-of-type-description.rst

@@ -0,0 +1,6 @@
+To query for objects of a given type in the database, pass the object type 
+``YourClassName`` to the :cpp-sdk:`db::objects\<T\> <structrealm_1_1db.html>`
+member function.
+
+This returns a :cpp-sdk:`Results <structrealm_1_1results.html>` object
+representing all objects of the given type in the database.

source/includes/api-details/cpp/crud/read-database-objects-procedure.rst

@@ -0,0 +1,25 @@
+To find objects stored within a database:
+
+1. Query for objects of a given type in the database, pass the object type 
+   ``YourClassName`` to the :cpp-sdk:`db::objects <structrealm_1_1db.html>`
+   member function.
+
+#. Optionally, pass any query conditions to further refine the results: 
+   
+   -  Specify a filter to only return objects that meet the condition. If 
+      you don't specify a filter, the SDK returns all objects of the specified 
+      type.
+   
+   -  Specify the sort order for the results. 
+      Because the database is unordered, if you don't include a sort order, 
+      the SDK cannot guarantee the query returns objects in any specific order.
+
+#. Work with the results. Objects may be frozen or live, depending on whether
+   you queried a frozen or live database, collection, or object.
+
+Note that any retrieved results don't actually hold matching database objects 
+in memory. Instead, the database uses **direct references**, or pointers. 
+Database objects in a results collection reference the matched objects, which
+map directly to data in the database file. This also means that you can
+traverse your graph of an object's :ref:`relationships <sdks-relationships>`
+directly through the results of a query.

source/includes/api-details/cpp/crud/read-filter-or-query-objects-description.rst

@@ -0,0 +1,11 @@
+To filter data, call the ``.where()`` function on a collection with a valid
+query. Currently, C++ supports only a subset of RQL operators.
+
+Supported Query Operators
+`````````````````````````
+
+C++ supports the following query operators:
+
+- Equality (``==``, ``!=``)
+- Greater than/less than (``>``, ``>=``, ``<``, ``<=``)
+- Compound queries (``||``, ``&&``)

source/includes/api-details/cpp/crud/read-find-object-by-primary-key-not-supported.rst

@@ -0,0 +1,3 @@
+C++ does not provide a dedicated API to find an object by its primary
+key. Instead, you can perform a regular query for objects where the primary
+key property matches the desired primary key value.

source/includes/api-details/cpp/crud/read-intro-description.rst

@@ -0,0 +1,7 @@
+Query operationsn return a :cpp-sdk:`results collection
+<structrealm_1_1results.html>`. Results collections may be either live or
+frozen.
+
+- **Live results** always contain the latest results of the associated query.
+- **Frozen results** represent a snapshot that cannot be modified and doesn't
+  reflect the latest changes to the database.

source/includes/api-details/cpp/crud/read-limit-not-supported.rst

@@ -0,0 +1,3 @@
+C++ does not provide an API to limit query results. Instead, rely on the
+SDK's lazy loading characteristics to implicitly limit the objects in
+memory by only accessing the objects you need for an operation.

source/includes/api-details/cpp/crud/read-query-dictionary-properties-description.rst

@@ -0,0 +1,3 @@
+You can iterate and check the values of a realm :cpp-sdk:`map property
+<structrealm_1_1managed_3_01std_1_1map_3_01std_1_1string_00_01T_01_4_00_01void_01_4.html>` 
+as you would a standard C++ `map <https://en.cppreference.com/w/cpp/container/map>`__.