[FEATURE] Make raw JSON REST requests to OpenSearch

[dblock]

Is your feature request related to a problem?

Developers want an easy, documented, way to make raw JSON REST requests to OpenSearch.

OpenSearch clients implement various high level DSLs to invoke OpenSearch APIs. Efforts such as #19 aim at always being up-to-date with the default distribution, including plugins. However this is a game that cannot be won because clients will always lag behind, even if a little. Furthermore, for custom plugins that aren't part of the distribution it may be too much overhead to build high level DSLs.

What solution would you like?

Implement and document an easy to use high level HTTP DSL in each client for making raw JSON requests.

• [FEATURE] Add the ability to send REST requests via the client opensearch-py#498
• [FEATURE] Raw Json support opensearch-java#257 [FEATURE] Enable Generic HTTP Actions in Java Client opensearch-java#910
• [FEATURE] Make raw JSON REST requests to OpenSearch opensearch-ruby#209
• [FEATURE] Make raw JSON REST requests to OpenSearch opensearch-js#631
• [FEATURE] Make raw JSON REST requests to OpenSearch opensearch-net#403
• [FEATURE] Make raw JSON REST requests to OpenSearch  opensearch-go#395
• [FEATURE] Make raw JSON REST requests to OpenSearch  opensearch-php#166
• [FEATURE] Make raw JSON REST requests to OpenSearch opensearch-rs#193

Do you have any additional context?

This is the umbrella issue. Please edit/tag related/child issues under this one.

[dblock]

Done across clients. Need to update my blog post on the topic with samples across all clients, https://code.dblock.org/2023/10/16/making-raw-json-rest-requests-to-opensearch.html.