config, cluster: add an option to halt the cluster scheduling (#6498)

[ti-chi-bot]

This is an automated cherry-pick of #6498

What problem does this PR solve?

Issue Number: ref #6493.

What is changed and how does it work?

Add an option to halt the cluster scheduling.

Check List

Tests

• Unit test
• Integration test

During the halt:

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• CabinfeverB
• bufferflies

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[HuSharp]

[HuSharp]

@nolouch @CabinfeverB @bufferflies show local test result PTAL, thx!

[codecov]

Codecov Report

Patch coverage: 68.96% and project coverage change: -0.01 ⚠️

Comparison is base (8e9d0c4) 75.64% compared to head (ddc7296) 75.64%.

Additional details and impacted files

@@               Coverage Diff               @@
##           release-6.5    #6558      +/-   ##
===============================================
- Coverage        75.64%   75.64%   -0.01%     
===============================================
  Files              330      330              
  Lines            33091    33113      +22     
===============================================
+ Hits             25033    25048      +15     
- Misses            5904     5907       +3     
- Partials          2154     2158       +4     

Flag	Coverage Δ
unittests	75.64% <68.96%> (-0.01%)	⬇️

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

Impacted Files	Coverage Δ
pkg/mock/mockcluster/mockcluster.go	93.76% <0.00%> (-0.23%)	⬇️
server/cluster/diagnostic_manager.go	76.34% <ø> (+4.30%)	⬆️
server/config/persist_options.go	92.90% <25.00%> (-0.24%)	⬇️
server/cluster/cluster.go	81.22% <66.66%> (-0.37%)	⬇️
server/cluster/coordinator.go	72.79% <75.00%> (+0.99%)	⬆️
server/cluster/cluster_worker.go	70.00% <100.00%> (ø)
server/cluster/metrics.go	100.00% <100.00%> (ø)
server/config/config.go	78.99% <100.00%> (+0.08%)	⬆️

... and 23 files with indirect coverage changes

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[bufferflies]

any test ??

[HuSharp]

The above figure shows the local test by tiup @bufferflies

[bufferflies]

/merge

[ti-chi-bot]

@bufferflies: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: ddc7296

[bufferflies]

/merge

[ti-chi-bot]

@bufferflies: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.