apis: add gang match policy alias annotation

[eahydra]

Ⅰ. Describe what this PR does

1. Move the Gang scheduling extension APIs to file apis/extension/coscheduling.go.
2. Add gang match policy alias pod-group.scheduling.sigs.k8s.io/match-policy to compatible with special scenarios.

Ⅱ. Does this pull request fix one issue?

Ⅲ. Describe how to verify it

Ⅳ. Special notes for reviews

V. Checklist

• I have written necessary docs and comments
• I have added necessary unit tests and integration tests
• All checks passed in make test

[codecov]

Codecov Report

Patch coverage has no change and project coverage change: -0.04% ⚠️

Comparison is base (2a23dd6) 64.80% compared to head (d0cd643) 64.77%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1530      +/-   ##
==========================================
- Coverage   64.80%   64.77%   -0.04%     
==========================================
  Files         347      347              
  Lines       35365    35365              
==========================================
- Hits        22920    22908      -12     
- Misses      10763    10774      +11     
- Partials     1682     1683       +1     

Flag	Coverage Δ
unittests	64.77% <ø> (-0.04%)	⬇️

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see 3 files with indirect coverage changes

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[hormes]

/lgtm
/approve

[koordinator-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hormes

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