Upcomming features for `saf generate delta`

[camdenmoors]

• [x] Ensure conversion between old and new rule IDs
• [ ] Special casing for CIS rule IDs as references
  • [ ] Extract Rule IDs from references
  • [x] Extract Rule IDs from rule ID (regex)
  • [ ] Discover other forms of CIS rule IDs
• [ ] Backwards compatibility with stubs generated with spreadsheet2inspec_stub