[res] Refactor AssetManager + Providers

- More moves where possible
- Better interface for PathOrDebugName creation
- function_ref as a callback
- Get rid of some obsolete Util.h code
- Shut up the logging in host mode, and ignore all calls

Bug: 237583012
Test: build + boot + UTs
Change-Id: Ia71fc1c83f17ab5ce3cac1179f74534f7ad2a3cb