feat: add NamespacedVerifier CRD [multi-tenancy PR 11]

[binbin-li]

Description

What this PR does / why we need it:

This is the 11th PR for multi-tenancy support. Please review #1423 first. Check diff between PR 10 and PR 11 at: binbin-li#144

1. Created new CRD: NamespacedVerifier for namespaced verifier resource and corresponding controller.
2. Updated implementaion of ActiveVerifiers so that it supports managing verifiers across namespaces.
3. Updated controllers to reduce duplicate code between namespaced and clustered controllers.
4. Moved all sample CRs under clustered/namespaced folders.
5. Added unit tests.

Which issue(s) this PR fixes (optional, using fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when the PR gets merged):

Fixes #

Type of change

Please delete options that are not relevant.

• 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 not work as expected)
• Helm Chart Change (any edit/addition/update that is necessary for changes merged to the main branch)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also list any relevant details for your test configuration

• Test A
• Test B

Checklist:

• Does the affected code have corresponding tests?
• Are the changes documented, not just with inline documentation, but also with conceptual documentation such as an overview of a new feature, or task-based documentation like a tutorial? Consider if this change should be announced on your project blog.
• Does this introduce breaking changes that would require an announcement or bumping the major version?
• Do all new files have appropriate license header?

Post Merge Requirements

• MAINTAINERS: manually trigger the "Publish Package" workflow after merging any PR that indicates Helm Chart Change

[codecov]

Codecov Report

Attention: Patch coverage is 81.91489% with 17 lines in your changes are missing coverage. Please review.

Project coverage is 66.73%. Comparing base (1bd347c) to head (653bded).
Report is 5 commits behind head on dev.

Files	Patch %	Lines
...ntrollers/namespaceresource/verifier_controller.go	80.00%	7 Missing and 1 partial ⚠️
pkg/manager/manager.go	0.00%	8 Missing ⚠️
...controllers/clusterresource/verifier_controller.go	85.71%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #1428      +/-   ##
==========================================
- Coverage   66.76%   66.73%   -0.03%     
==========================================
  Files         116      119       +3     
  Lines        6030     6133     +103     
==========================================
+ Hits         4026     4093      +67     
- Misses       1620     1659      +39     
+ Partials      384      381       -3     

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[akashsinghal]

LGTM. Thanks

The merge-base changed after approval.

[binbin-li]

LGTM. Thanks

@akashsinghal thanks for your review! Just merged dev to resolve the conflicts, could you have another quick review? There should be no diff in this patch.