cluster: add additional prom scrape_configs

[nexustar]

What problem does this PR solve?

• close TiUP support user-defined prome configuration during reload #1615

What is changed and how it works?

user may use like this:

Check List

Tests

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

Code changes

• Has exported function/method change
• Has exported variable/fields change
• Has interface methods change
• Has persistent data change

Side effects

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

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Release notes:

NONE

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• AstroProfundis

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[codecov-commenter]

Codecov Report

Merging #1641 (1b21c48) into master (592b46c) will increase coverage by 18.85%.
The diff coverage is 0.00%.

@@             Coverage Diff             @@
##           master    #1641       +/-   ##
===========================================
+ Coverage   15.57%   34.43%   +18.85%     
===========================================
  Files         151      232       +81     
  Lines       15254    21821     +6567     
===========================================
+ Hits         2376     7513     +5137     
- Misses      12361    13173      +812     
- Partials      517     1135      +618     

Flag	Coverage Δ
cluster	34.43% <0.00%> (?)
integrate	34.43% <0.00%> (+18.85%)	⬆️
tiup	?

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

Impacted Files	Coverage Δ
pkg/cluster/spec/monitoring.go	56.59% <0.00%> (+56.59%)	⬆️
pkg/repository/store/store.go	0.00% <0.00%> (-100.00%)	⬇️
pkg/repository/utils/hash.go	0.00% <0.00%> (-83.34%)	⬇️
pkg/repository/model/publish.go	0.00% <0.00%> (-83.34%)	⬇️
pkg/repository/store/local.go	0.00% <0.00%> (-82.61%)	⬇️
pkg/repository/progress.go	23.07% <0.00%> (-76.93%)	⬇️
pkg/telemetry/meta.go	0.00% <0.00%> (-67.40%)	⬇️
pkg/telemetry/telemetry.go	0.00% <0.00%> (-66.67%)	⬇️
pkg/repository/v1manifest/keys.go	5.33% <0.00%> (-58.67%)	⬇️
pkg/repository/merge_mirror.go	0.00% <0.00%> (-58.51%)	⬇️
... and 210 more

---

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[AstroProfundis]

I don't think the nested multi-line config is a good idea.

We had been using nested multi-line format for the server_config and xxx.config fields in early versions of tiup-cluster, the result was getting issues and bug reports about "the config is incorrect" or "the config can not be applied" every week due to wrong indents user input.

There are many editors trying to automatically prepending indents when you edit the file, that's sweet in most cases, but not working well when there is anything nested and will be used to another file with different structure.

-- edit

Oh I see it's not a nested multi-line config string, but rather a map[string]interface{} struct. It seems that could do the trick, we'll need some tests about wired user inputs.

[AstroProfundis]

/merge

[ti-chi-bot]

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

Commit hash: 1b21c48