Adds a basic generic prefix matcher type. The
first implementation just uses a map and iterates
through things
This is expected to be used for at least the
exclude list for backups (inner type of
`map[string]struct{}`) and logic for merging
backup details (inner type still TBD a bit,
but either `*path.Builder` or a custom struct)
---
#### Does this PR need a docs update or release note?
- [ ] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [x] ⛔ No
#### Type of change
- [x] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup
#### Issue(s)
* #2486
#### Test Plan
- [ ] 💪 Manual
- [x] ⚡ Unit test
- [ ] 💚 E2E
