feat(pipeline): join processor

[shuiyisong]

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?

Porting https://github.com/GreptimeTeam/pipeline/pull/44

Implement join processor

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR requires documentation updates.

[codecov]

Codecov Report

Attention: Patch coverage is 76.25000% with 19 lines in your changes missing coverage. Please review.

Project coverage is 84.62%. Comparing base (0fc18b6) to head (df7a9ea).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4158      +/-   ##
==========================================
- Coverage   84.92%   84.62%   -0.31%     
==========================================
  Files        1023     1024       +1     
  Lines      179298   179378      +80     
==========================================
- Hits       152272   151791     -481     
- Misses      27026    27587     +561     

[killme2008]

LGTM