(DOCSP-42133): Update BackingDB, MongoDB, and agent support matrices for OM 8.0 (#378)

<!-- Add a description of your PR here (optional) -->
## Description
- Updates BackingDB and MongoDB support tables for OM 8.0
- Updates Agent support table for OM 8.0 (same table as
10gen/docs-cloud-manager#59, **which has already
been reviewed/approved**)

These are based on
https://docs.google.com/spreadsheets/d/1nTvZ2cTg2Ef2XweyV1ZBb7BMSYO4eKqXszfqkpBsOPM/edit#gid=228572960

### Links
- [DOCSP-42133](https://jira.mongodb.org/browse/DOCSP-42133)
- Staging:
-
https://deploy-preview-378--10gen-docs-ops-manager.netlify.app/tutorial/prepare-backing-mongodb-instances/#use-a-compatible-mongodb-version
-
https://deploy-preview-378--10gen-docs-ops-manager.netlify.app/reference/mongodb-compatibility/
-
https://deploy-preview-378--10gen-docs-ops-manager.netlify.app/tutorial/install-mongodb-agent-prereq/


### Self-Review Checklist

- [ ]
[Define](https://wiki.corp.mongodb.com/display/DE/Taxonomy+tagging+instructions)
taxonomy
[values](https://wiki.corp.mongodb.com/display/DE/Docs+Taxonomy) at top
of page.
- [ ] Add genre facets (tutorial or reference), as in this [example
PR](10gen/cloud-docs#5042).
- [ ] Add programmingLanguage (if necessary).
- [ ] Add meta keywords (if necessary).
- [x] Resolve any new warnings or errors in the build.
- [x] Proofread for spelling and grammatical errors.
- [x] Check staging for rendering issues.
- [x] Confirm links are working.

Author: davidhou17

source/core/requirements.txt

@@ -456,7 +456,7 @@ the following hardware architectures and operating systems. The
 following table lists the MongoDB Server versions that you can deploy 
 with the {+mdbagent+} on the associated platforms:
 
-.. include:: /includes/list-tables/v7-agent-platform-support-table.rst 
+.. include:: /includes/list-tables/v8-agent-platform-support-table.rst 
 
 Intel/AMD (``x86_64``) Hardware Architectures
 +++++++++++++++++++++++++++++++++++++++++++++

source/includes/list-tables/supported-backingdb-versions.rst

@@ -1,25 +1,35 @@
 .. list-table:: Supported Versions of MongoDB for Each Version of |onprem|
    :header-rows: 1
    :stub-columns: 1
-   :widths: 40 15 15 15 15
+   :widths: 25 15 15 15 15 15
 
    * - |onprem| Release
      - MongoDB 4.4
      - MongoDB 5.0
      - MongoDB 6.0
      - MongoDB 7.0
+     - MongoDB 8.0
 
-   * - |onprem| 7.0
+   * - |onprem| 8.0
+     - 
      - 
      - Deprecated
      - Supported
      - Supported
 
+   * - |onprem| 7.0
+     - 
+     - Deprecated
+     - Supported
+     - Supported
+     - 
+
    * - |onprem| 6.0
      - Deprecated
      - Supported
      - Supported
      - 
+     -
 
 .. include:: /includes/deprecated-definition.rst
 

source/includes/list-tables/supported-mongodb-versions.rst

@@ -4,31 +4,43 @@
    :widths: 34 33 33
 
    * - MongoDB Version
+     - |onprem| 8.0
      - |onprem| 7.0
      - |onprem| 6.0
 
+   * - MongoDB 8.0
+     - Supported
+     - 
+     -
+
    * - MongoDB 7.0
+     - Supported
      - Supported
      - 
 
    * - MongoDB 6.0
      - Supported
      - Supported
+     - Supported
 
    * - MongoDB 5.0
+     - Deprecated
      - Supported
      - Supported
 
    * - MongoDB 4.4
+     - Deprecated
      - Supported
      - Supported
 
    * - MongoDB 4.2
+     - 
      - Deprecated
      - Supported
 
    * - MongoDB 4.0
      - 
+     -
      - Deprecated
 
    * - MongoDB 3.6