Camera: Add initial flagging support

- Add core aconfig file into frameworks/av/camera
- Add various flag libraries for use across camera stack

Test: Manual:
 - Test flag library can be called in camera service
 - Test flag can be flipped by tooling
Bug: 297375200
Change-Id: Ic008f6442a27f0fe5579a1f18b5e9470754b8db4