Add Helm configuration for feature flags

[evankanderson]

Summary

Adds the ability to control configured Minder flags by creating a ConfigMap named minder-flags containing a key flags-config.yaml using a GoFeatureFlag config file.

See https://gofeatureflag.org/editor for a UI editor for the same.

Fixes #3187

Change Type

Mark the type of change your PR introduces:

• Bug fix (resolves an issue without affecting existing features)
• Feature (adds new functionality without breaking changes)
• Breaking change (may impact existing functionalities or require documentation updates)
• Documentation (updates or additions to documentation)
• Refactoring or test improvements (no bug fixes or new functionality)

Testing

I used my brain, sorry!

Review Checklist:

• Reviewed my own code for quality and clarity.
• Added comments to complex or tricky code sections.
• Updated any affected documentation.
• Included tests that validate the fix or feature.
• Checked that related changes are merged.

[coveralls]

coverage: 50.517% (-0.02%) from 50.534%
when pulling 7db2b22 on evankanderson:3187-allow-configuring-flags-in-helm-chart
into d8f7d57 on stacklok:main.