feat: employ sparse key encoding for shard lookup

[v0y4g3r]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

This PR employs spase key encoding to encode primary keys to bytes for primary key to pk id look up.

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR does not require documentation updates.

Refer to a related PR or issue link (optional)

[codecov]

Codecov Report

Attention: Patch coverage is 72.52747% with 25 lines in your changes are missing coverage. Please review.

Project coverage is 84.61%. Comparing base (3413fc0) to head (4a28cad).
Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3410      +/-   ##
==========================================
- Coverage   85.06%   84.61%   -0.45%     
==========================================
  Files         889      889              
  Lines      146280   146398     +118     
==========================================
- Hits       124428   123871     -557     
- Misses      21852    22527     +675     

[evenyag]

Mostly LGTM

[fengjiachun]

LGTM