koordlet: add external prom metrics collector

[saintube]

Ⅰ. Describe what this PR does

• koordlet: support the prom collector. With a YAML configuration, it scrapes the prom metrics of external Prometheus exporters and stores them into the koordlet metric cache.

Ⅱ. Does this pull request fix one issue?

fixes #1735.

Ⅲ. Describe how to verify it

Ⅳ. Special notes for reviews

V. Checklist

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

[koordinator-bot[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: To complete the pull request process, please assign yihuifeng after the PR has been reviewed. You can assign the PR to them by writing /assign @yihuifeng in a comment when ready.

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[codecov[bot]]

Codecov Report

Attention: Patch coverage is 65.55423% with 289 lines in your changes are missing coverage. Please review.

Project coverage is 66.43%. Comparing base (7ca45d7) to head (38bb143). Report is 106 commits behind head on main.

Files	Patch %	Lines
...koordlet/metricsadvisor/collectors/prom/scraper.go	73.66%	55 Missing and 29 partials :warning:
...t/metricsadvisor/collectors/prom/prom_collector.go	55.81%	33 Missing and 5 partials :warning:
...et/metricsadvisor/collectors/prom/scrape_client.go	71.59%	20 Missing and 5 partials :warning:
...let/qosmanager/plugins/cpusuppress/cpu_suppress.go	20.00%	16 Missing :warning:
pkg/koordlet/metrics/common.go	68.75%	10 Missing and 5 partials :warning:
...let/metricsadvisor/collectors/prom/collect_rule.go	88.23%	8 Missing and 4 partials :warning:
...collectors/noderesource/node_resource_collector.go	22.22%	5 Missing and 2 partials :warning:
...visor/collectors/pagecache/page_cache_collector.go	46.15%	6 Missing and 1 partial :warning:
...ollectors/sysresource/system_resource_collector.go	50.00%	5 Missing and 2 partials :warning:
...let/qosmanager/plugins/memoryevict/memory_evict.go	25.00%	6 Missing :warning:
... and 22 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1772      +/-   ##
==========================================
+ Coverage   66.42%   66.43%   +0.01%     
==========================================
  Files         396      401       +5     
  Lines       43721    44526     +805     
==========================================
+ Hits        29040    29581     +541     
- Misses      12529    12741     +212     
- Partials     2152     2204      +52     

Flag	Coverage Δ
unittests	66.43% <65.55%> (+0.01%)	:arrow_up:

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[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. This bot triages issues and PRs according to the following rules:

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[stale[bot]]

This issue has been automatically closed because it has not had recent activity. This bot triages issues and PRs according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, the issue is closed You can:
• Reopen this PR with /reopen Thank you for your contributions.