Refactor how to handle sigterm and nginx process goroutine

[aledbf]

What this PR does / why we need it:

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Which issue/s this PR fixes

How Has This Been Tested?

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have added tests to cover my changes.
• All new and existing tests passed.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aledbf

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• OWNERS [aledbf]

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[codecov-io]

Codecov Report

Merging #4959 into master will decrease coverage by 0.02%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #4959      +/-   ##
==========================================
- Coverage   58.48%   58.45%   -0.03%     
==========================================
  Files          88       88              
  Lines        6728     6728              
==========================================
- Hits         3935     3933       -2     
- Misses       2363     2364       +1     
- Partials      430      431       +1

Impacted Files	Coverage Δ
cmd/nginx/main.go	6.49% <0%> (ø)	⬆️
internal/ingress/controller/nginx.go	29.69% <0%> (ø)	⬆️
internal/ingress/metric/collectors/process.go	88.29% <0%> (-2.13%)	⬇️

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[aledbf]

/retest

[aledbf]

/retest

[aledbf]

/retest

[aledbf]

/retest

[aledbf]

/retest