feat: add count with filtering + fields operations to ElasticSearch document store

[davidsbatista]

Related Issues

• fixes add the following operations to ElasticsearchDocumentStore #2636

Proposed Changes:

Adding more operations to this DocumentStore, namely:

count_documents_by_filter()
count_distinct_values_by_filter()
get_fields_info()
get_field_min_max()
get_field_unique_values()
query_sql()

along with the async version of each

How did you test it?

• added integration tests for each function both for sync and async versions

Notes for the reviewer

• In a next PR we should separate the sync and async tests, since the file is already above 1k lines

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added unit tests and updated the docstrings
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test:.

[davidsbatista]

@tstadel adding you as well, but more for awareness and if you want to give a quick look
@sjrl since ElasticSearch API is very similar to OpenSearch I've added you but feel free to unassign yourself and add someone else