Introduce Enforce flag on Policy CRD

[waleedhammam]

Closes #210

What changed?

• Introduce enforce flag on policy agent CRD to define whether a policy is enforced via the admission controller or just audited for a violation.
• Remove enabled flag as it's no longer used

Why was this change made?

• To replace the PolicySet feature

How was this change implemented?

• Update the CRD to have the new flag and delete the old one
• Update policy-core package to include the new flag
• Update internal package to use the new flag
• Update tests

How did you validate the change?

Release notes

Documentation Changes

[codecov-commenter]

Codecov Report

Attention: 3 lines in your changes are missing coverage. Please review.

Comparison is base (adbb15f) 78.34% compared to head (b7b0cbe) 78.35%.

Files	Patch %	Lines
pkg/policy-core/domain/policy_validation.go	66.66%	1 Missing and 1 partial ⚠️
pkg/policy-core/validation/opa_validation.go	75.00%	1 Missing ⚠️

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev     #216      +/-   ##
==========================================
+ Coverage   78.34%   78.35%   +0.01%     
==========================================
  Files          20       20              
  Lines        1279     1289      +10     
==========================================
+ Hits         1002     1010       +8     
- Misses        211      212       +1     
- Partials       66       67       +1     

Flag	Coverage Δ
unit	78.35% <82.35%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[Samra10]

LGTM. ✅

Tested on both cases when Enforce flag is enabled & disabled, and Enforce flag exist on the violation events.