scheduler: add scheduler type and move metrics file

[okJiang]

What problem does this PR solve?

Issue Number: Ref #8379

What is changed and how does it work?

as title

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Code changes

• Has the configuration change
• Has HTTP API interfaces changed (Don't forget to add the declarative for the new API)
• Has persistent data change

Side effects

• Possible performance regression
• Increased code complexity
• Breaking backward compatibility

Related changes

• PR to update pingcap/docs/pingcap/docs-cn:
• PR to update pingcap/tiup:
• Need to cherry-pick to the release branch

Release note

None.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.19%. Comparing base (0b5ed0f) to head (1aef158).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8393      +/-   ##
==========================================
- Coverage   77.21%   77.19%   -0.02%     
==========================================
  Files         471      471              
  Lines       61806    61834      +28     
==========================================
+ Hits        47723    47734      +11     
- Misses      10491    10506      +15     
- Partials     3592     3594       +2     

Flag	Coverage Δ
unittests	77.19% <100.00%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

[okJiang]

/cc @JmPotato @nolouch @rleungx

Could you help me to take a look for this pr? It is very simple.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: JmPotato, rleungx

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• OWNERS [JmPotato,rleungx]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-07-17 01:58:35.623763605 +0000 UTC m=+405537.614705074: ☑️ agreed by rleungx.
• 2024-07-17 03:32:48.285646804 +0000 UTC m=+411190.276588276: ☑️ agreed by JmPotato.