feat: merge tree dedup reader

[v0y4g3r]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

This PR:

• adds dedup config to Shard/ShardBuilder/DataBuffer etc. to control whether rows with duplicate ts should be removed
• impls DedupReader so that we can remove duplicated rows among different data batches.

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)

• Tracking issue for the memtable improvement #2804

[codecov]

Codecov Report

Attention: Patch coverage is 89.03654% with 33 lines in your changes are missing coverage. Please review.

Project coverage is 85.18%. Comparing base (1df64f2) to head (7752a11).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3375      +/-   ##
==========================================
- Coverage   85.59%   85.18%   -0.41%     
==========================================
  Files         892      893       +1     
  Lines      146564   146815     +251     
==========================================
- Hits       125448   125070     -378     
- Misses      21116    21745     +629     

[evenyag]

LGTM

[fengjiachun]

LGTM