feat: add vulnerability scanner [PROTOTYPE]

[akashsinghal]

Description

What this PR does / why we need it:

• Adds a sample vulnerability report verifier
• Works with Trivy and Grype reports
• Enforces a maximumAge for reports
• checks for disallowed severity levels in the report

Sample:

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: 5 lines in your changes are missing coverage. Please review.

Comparison is base (52c2c00) 52.39% compared to head (32394b1) 52.56%.
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1123      +/-   ##
==========================================
+ Coverage   52.39%   52.56%   +0.16%     
==========================================
  Files         101      102       +1     
  Lines        6344     6377      +33     
==========================================
+ Hits         3324     3352      +28     
- Misses       2699     2704       +5     
  Partials      321      321              

Files	Coverage Δ
...rabilityreport/schemavalidation/schemavalidator.go	84.84% <84.84%> (ø)

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[akashsinghal]

Close in favor of #1173