Feature: rpc blockbyheight

[rdeioris]

Description

Hi, this is my initial attempt at approaching the codebase by covering an issue out of the critical path. This patch
adds a new RPC call: /v3/blocks/height/{block_height} as specified in issue #4358

Applicable issues

• fixes Add additional GET RPC endpoints #4358

Additional info (benefits, drawbacks, caveats)

The endpoint is fork-safe as it allows to specify an additional query_string (?tip=x) that will force the search in the MARF for a specific tip block hash

Checklist

• [x ] Test coverage for new or modified code paths
• [x ] Changelog is updated
• [ x] Required documentation changes (e.g., docs/rpc/openapi.yaml and rpc-endpoints.md for v2 endpoints, event-dispatcher.md for new events)
• New clarity functions have corresponding PR in clarity-benchmarking repo
• [x ] New integration test(s) added to bitcoin-tests.yml

[rdeioris]

Updated the pull request for including only the /v3/blocks/height endpoint with the fix for using the MARF for querying from a secific tip. The patch is now less invasive (basically it is self-contained)

[jcnelson]

LGTM. Just need to get CI to pass.

[hstove]

@rdeioris I see you've updated rpc-endpoints.md, but please also update docs/rpc/openapi.yaml with this new endpoint. Thanks!

[obycode]

This looks good, just flagged a couple of typos. I also second Hank's request to update the openapi.yml.