Add aggs parsers for high level REST Client

[javanna]

This PR contains the work that has been done on adding parsers for aggregations responses in the feature/client_aggs_parsing branch. All of the aggregations are now supported hence the branch can be merged to master, later on #24796 can be merged to master too so that the high level REST client finally supports _search.

Rather than reusing the classes that already existed for aggregations (which we have done for other apis, or other sections of search), we went for implementing the aggregations interfaces but creating our own classes that we parse responses into. This is because the existing classes are internal classes that hold quite some internal state which would not be available when parsing response back from the REST layer.

The following are all the PRs that were merged to the branch:

• Add ParsedAggregation as base Aggregation impl for high level client (Add ParsedAggregation as base Aggregation impl for high level client #23965)
• Adding ParsedCardinality (Adding ParsedCardinality #23973)
• Add parsing for percentiles ranks (Add parsing for percentiles ranks #23974)
• Add parsing to some single value aggregations (Add parsing to some single value aggregations #24085)
• AbstractParsedPercentiles should use Percentile class (AbstractParsedPercentiles should use Percentile class #24160)
• Add parsing for InternalSimpleValue and InternalDerivative (Add parsing for InternalSimpleValue and InternalDerivative #24162)
• Add parsing for InternalBucketMetricValue (Add parsing for InternalBucketMetricValue #24182)
• Add parsing methods for Percentiles aggregations (Add parsing methods for Percentiles aggregations #24183)
• [Test] Always check the XContent equivalent when parsing aggregations ( [Test] Always check the XContent equivalent when parsing aggregations #24208)
• Add parsing methods for InternalDateHistogram and InternalHistogram (Add parsing methods for InternalDateHistogram and InternalHistogram #24213)
• Add parsing for InternalStats (Add parsing for InternalStats #24239)
• Add parsing for InternalExtendedStats (Add parsing for InternalExtendedStats #24284)
• Add parsing for InternalStatsBucket and InternalExtendedStatsBucket (Add parsing for InternalStatsBucket and InternalExtendedStatsBucket #24312)
• Add parsing for InternalPercentilesBucket (Add parsing for InternalPercentilesBucket #24330)
• Add parsing for InternalGeoBounds (Add parsing for InternalGeoBounds #24365)
• Add parsing for InternalGeoCentroid (Add parsing for InternalGeoCentroid #24371)
• Introduce SearchResponseSections base class (Introduce SearchResponseSections base class #24442)
• Add parsing for String/Long/Double Terms aggregations (Add parsing for String/Long/Double Terms aggregations #24521)
• [TEST] Add test for Aggregations#fromXContent ([TEST] Add test for Aggregations#fromXContent #24524)
• Add parsing for single bucket aggregations (Add parsing for single bucket aggregations #24564)
• Add parsing methods to Range aggregations (Add parsing methods to Range aggregations #24583)
• Add parsing method to GeoHashGrid aggregation (Add parsing method to GeoHashGrid aggregation #24589)
• Add parsing for InternalFilters aggregation (Add parsing for InternalFilters aggregation #24648)
• Revert changing the InternalSampler type constant (Revert changing the InternalSampler type constant #24667)
• Small improvement in InternalAggregationTestCase test setup (Small improvement in InternalAggregationTestCase test setup  #24675)
• Add parsing to Significant Terms aggregations (Add parsing to Significant Terms aggregations #24682)
• Add parsing for InternalAdjacencyMatrix aggregation (Add parsing for InternalAdjacencyMatrix aggregation #24700)
• Add parsing method for binary range aggregation (Add parsing method for binary range aggregation #24706)
• Add parsing method for Top Hits aggregation (Add parsing method for Top Hits aggregation #24717)
• Add fromXContent method to SearchResponse (Add fromXContent method to SearchResponse #24720)
• Add parsing for InternalScriptedMetric aggregation (Add parsing for InternalScriptedMetric aggregation #24738)
• Add parsing method for Matrix Stats (Add parsing method for Matrix Stats #24746)
• Remove //norelease and cleans up some aggregations tests (Remove //norelease and cleans up some aggregations tests #24789)
• [Test] Remove ParsedAggregationTests ([Test] Remove ParsedAggregationTests #24791)
• SearchResponse#fromXContent to not require START_OBJECT as current token (SearchResponse#fromXContent to not require START_OBJECT as current token #24794)
• Move getType to Aggregation interface (Move getType to Aggregation interface #24822)

[s1monw]

formal LGTM - lets get this in!