feat(tql): add initial support for start,stop,step as sql functions

[etolbakov]

I hereby agree to the terms of the GreptimeDB CLA.

Refer to a related PR or issue link (optional)

#3452
#3453 (lookback parameter)

What's changed and what's your intention?

TQL parser accepts SQL functions such as now() for start,end and step parameters:

Please explain IN DETAIL what the changes are in this PR and why they are needed:

• enhanced the tql_parser logic with small pre-planning and pre-executing phases to evaluate start,end and step into number (timestamp) if those parameter were passed as SQL functions; The logic is the following
  1. converting the function into “logical” expr
  2. using simplifier evaluate expr.

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.

[etolbakov]

add lookback param support for TQL EVAL
#3453
Happy to add more logic to accomplish the ticket

[codecov]

Codecov Report

Attention: Patch coverage is 88.91403% with 49 lines in your changes are missing coverage. Please review.

Project coverage is 85.07%. Comparing base (63681f0) to head (1abf153).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3507      +/-   ##
==========================================
- Coverage   85.41%   85.07%   -0.35%     
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  Files         931      931              
  Lines      154531   154806     +275     
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- Hits       131997   131696     -301     
- Misses      22534    23110     +576     

[waynexia]

Thanks for taking this! I left some style sugg.:

[killme2008]

Looks great!

[killme2008]

LGTM

[waynexia]

Thanks for this!

[etolbakov]

Thank you @waynexia for useful tips(especially with the simplification) and help during the implementation!
It was a great pleasure to collaborate on this ticket!

[waynexia]

Thanks for keeping working on this huge and exciting feature. I can't wait to try it out!