feat(fuzz): add insert target

[zhongzc]

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Refer to a related PR or issue link (optional)

#3174

What's changed and what's your intention?

Insert expr generator:

• Allow omitting some columns or omit all columns
• Allow generating null or default

value generator:

• make timestamp, datetime and date to generate valid value

Add insert target

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.

[codecov]

Codecov Report

Attention: Patch coverage is 73.88060% with 35 lines in your changes are missing coverage. Please review.

Project coverage is 84.91%. Comparing base (904484b) to head (4645fc0).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3499      +/-   ##
==========================================
- Coverage   85.31%   84.91%   -0.41%     
==========================================
  Files         903      904       +1     
  Lines      149704   149803      +99     
==========================================
- Hits       127727   127209     -518     
- Misses      21977    22594     +617