Add pathfilter

What does this MR do?

Adds a filter so that the secrets analyzer respects SAST_EXCLUDED_PATHS

Output from running this locally since we don't really have a solid way of testing the cli commands holistically

No exclude paths:

Excluded:

paths:

Commit that kicked off excluded pipeline:

What are the relevant issue numbers?

gitlab-org/gitlab#196866 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template
  • Job definition example
  • CI Templates
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer