chore(mito): change default batch size/row group size

[evenyag]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

Change default batch size and row group size to 1024 and 100 * 1024.

Arrow aligns its buffer to a multiple of 64 so our old default batch size (1000) wastes some slots.

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.

Refer to a related PR or issue link (optional)

[codecov]

Codecov Report

Merging #2550 (b3e4dfa) into develop (8cc862f) will decrease coverage by 0.37%.
Report is 2 commits behind head on develop.
The diff coverage is 100.00%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2550      +/-   ##
===========================================
- Coverage    85.36%   84.99%   -0.37%     
===========================================
  Files          737      737              
  Lines       117542   117545       +3     
===========================================
- Hits        100334    99904     -430     
- Misses       17208    17641     +433     

[fengjiachun]

LGTM

[v0y4g3r]

LGTM