feature: add lantency metrics for yurthub

[luc99hen]

What type of PR is this?

/kind feature

What this PR does / why we need it:

The latency collector is used to collect yurthub request latency metrics, and the latency metrics can be divided into two categories:

• apiserver_latency: requests forward by proxy server -> api server -> received by proxy server
• full_latency: requests comming to proxy server -> processing by proxy server -> api server -> received by proxy server -> proxy server handling

Special notes for your reviewer:

The full latency start recording after inflight requests limits has been applied, because latency of blocked requests is of no use.

Does this PR introduce a user-facing change?

other Note

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In response to this:

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespace from that line:
/kind bug
/kind documentation
/kind enhancement
/kind good-first-issue
/kind feature
/kind question
/kind design
/sig ai
/sig iot
/sig network
/sig storage

What this PR does / why we need it:

The latency collector is used to collect yurthub request latency metrics, and the latency metrics can be divided into two categories:

• apiserver_latency: requests forward by proxy server -> api server -> received by proxy server
• full_latency: requests comming to proxy server -> processing by proxy server -> api server -> received by proxy server -> proxy server handling

Special notes for your reviewer:

The full latency start recording after inflight requests limits has been applied, because latency of blocked requests is of no use.

Does this PR introduce a user-facing change?

other Note

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 kubernetes/test-infra repository.

[codecov]

Codecov Report

Merging #965 (09ef791) into master (8896ea6) will increase coverage by 0.82%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #965      +/-   ##
==========================================
+ Coverage   43.59%   44.42%   +0.82%     
==========================================
  Files          83       83              
  Lines       11260    11370     +110     
==========================================
+ Hits         4909     5051     +142     
+ Misses       5914     5882      -32     
  Partials      437      437              

Flag	Coverage Δ
unittests	44.42% <100.00%> (+0.82%)	⬆️

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

Impacted Files	Coverage Δ
pkg/yurthub/proxy/util/util.go	87.61% <100.00%> (+17.72%)	⬆️
...troller/nodelifecycle/node_lifecycle_controller.go	56.15% <0.00%> (+0.60%)	⬆️
pkg/yurthub/filter/servicetopology/handler.go	59.43% <0.00%> (+18.94%)	⬆️

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[rambohe-ch]

@luc99hen please fix codecov errors.

[openyurt-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: luc99hen, rambohe-ch

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• OWNERS [rambohe-ch]

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[rambohe-ch]

/lgtm
/approve