koord-manager: add metrics for webhook

[nce3xin]

koord-manager: add metrics for webhook

[codecov]

Codecov Report

Attention: Patch coverage is 67.41573% with 29 lines in your changes missing coverage. Please review.

Project coverage is 66.05%. Comparing base (37bd292) to head (1db09bc).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/webhook/pod/mutating/mutating_handler.go	60.00%	8 Missing ⚠️
pkg/webhook/cm/validating/validating_handler.go	0.00%	5 Missing ⚠️
pkg/webhook/pod/validating/validating_handler.go	77.27%	4 Missing and 1 partial ⚠️
pkg/webhook/metrics/webhook_duration.go	75.00%	2 Missing and 1 partial ⚠️
.../webhook/elasticquota/mutating/mutating_handler.go	60.00%	2 Missing ⚠️
...k/elasticquota/plugin_check_quota_meta_validate.go	0.00%	2 Missing ⚠️
pkg/webhook/node/mutating/mutating_handler.go	60.00%	2 Missing ⚠️
pkg/webhook/node/validating/validating_handler.go	60.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2330      +/-   ##
==========================================
+ Coverage   66.03%   66.05%   +0.01%     
==========================================
  Files         461      464       +3     
  Lines       54547    54643      +96     
==========================================
+ Hits        36022    36095      +73     
- Misses      15918    15942      +24     
+ Partials     2607     2606       -1     

Flag	Coverage Δ
unittests	66.05% <67.41%> (+0.01%)	⬆️

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[saintube]

/lgtm

[zwzhang0107]

/approve