chore: add versioned apis

[arriqaaq]

Description

This PR does the following

1. Adds the following versioned APIs to the snapshot and tree
   • get_at_ts (to get a key at a particular timestamp)
   • get_all_versions (to get all the versions of a key)
   • scan_at_ts (scans all keys at a timestamp)
   • keys_at_ts (query all keys at a timestamp)
2. Avoid returning the key from all the get APIs
3. Shorten function name insert_without_version_increment_check ---> insert_unchecked
4. Fix an issue with duplicate insertion (two keys with the same version) into the twig node, where the duplicate node is not sorted by timestamp
5. Add get_value_by_query to both tree and snapshot to query the value by the following query types
   • LatestByVersion
   • LatestByTs
   • LastLessThanTs
   • LastLessOrEqualTs
   • FirstGreaterThanTs
   • FirstGreaterOrEqualTs

[gsserge]

🚀