feat: add profile feature for agent, and fix logr's panic

[alswl]

Feature

Using env variables to enable profiling mode, the agent can be started with the following envs:

export GITOPS_ENGINE_PROFILE=web
# optional, default pprofile address is 127.0.0.1:6060
export GITOPS_ENGINE_PROFILE_HOST=127.0.0.1
export GITOPS_ENGINE_PROFILE_PORT=6060

And then you can open profile in the browser(or using pprof cmd to generate diagrams):

• http://127.0.0.1:6060/debug/pprof/goroutine?debug=2
• http://127.0.0.1:6060/debug/pprof/mutex?debug=2

Fix

logr will panic when format with none string params, error meesage:

key is not a string: "error creating gvk parser: duplicate entry for /v1, Kind=WatchEvent"

[sonarcloud[bot]]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[codecov[bot]]

Codecov Report

Merging #444 (c90b78a) into master (2bc3fef) will not change coverage. The diff coverage is 0.00%.

@@           Coverage Diff           @@
##           master     #444   +/-   ##
=======================================
  Coverage   55.22%   55.22%           
=======================================
  Files          41       41           
  Lines        4449     4449           
=======================================
  Hits         2457     2457           
  Misses       1803     1803           
  Partials      189      189           

Impacted Files	Coverage Δ
pkg/cache/cluster.go	54.86% <0.00%> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[alswl]

@alexmt @jannfis Please code review when you have time.

[alswl]

ping @terrytangyuan