Add an Iterator over Properties

[jhrozek]

Summary

Uses the new Go 1.23 feature to implement an iterator over properties.
This will simplify the future code.

Related: #4171

Change Type

• 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

part of a larger branch

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: 53.738% (+0.02%) from 53.716%
when pulling 97ea006 on jhrozek:prop_iter
into b30ca2e on stacklok:main.