feat: allow cross-schema query in promql

[sunng87]

I hereby agree to the terms of the GreptimeDB CLA.

Refer to a related PR or issue link (optional)

What's changed and what's your intention?

This patch adds special matcher __schema__ for our promql parser for selecting a schema where the table sits. This allows user to do cross-schema query in promql.

The patch also does some refactoring in promql parser.

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 94.87179% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 85.06%. Comparing base (14267c2) to head (d2be785).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3545      +/-   ##
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- Coverage   85.40%   85.06%   -0.34%     
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  Files         931      931              
  Lines      154826   154941     +115     
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- Hits       132224   131800     -424     
- Misses      22602    23141     +539     

[sunng87]

Updated

[sunng87]

@waynexia PTAL

[waynexia]

Looking good. Would prefer to also add some sqlness test

[sunng87]

Do we have sqlness for promql? I didn't see them so I added tests in tests-integration.

[killme2008]

Do we have sqlness for promql? I didn't see them so I added tests in tests-integration.

Rerfer to https://github.com/GreptimeTeam/greptimedb/tree/main/tests/cases/standalone/common/tql

[waynexia]

👍