feat: sqlness for decimal128

[QuenKar]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

some sqlness test cases for decimal128 type,
and include

• common select.
• create, insert, delete, drop, subquery, join, order by.
• decimal cast with numeric, string, decimal itself.
• math operators and some aggregation function.

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)

Closes #2682

[codecov]

Codecov Report

Merging #2822 (2b36c5d) into develop (bd9c2f2) will decrease coverage by 0.39%.
Report is 11 commits behind head on develop.
The diff coverage is n/a.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2822      +/-   ##
===========================================
- Coverage    84.78%   84.39%   -0.39%     
===========================================
  Files          734      734              
  Lines       114927   115175     +248     
===========================================
- Hits         97440    97204     -236     
- Misses       17487    17971     +484     

[killme2008]

Great job! Thank u!

[killme2008]

@v0y4g3r @evenyag @waynexia Please take a look.