KeyguardBottomAreaView new impl. - UI layer

- In this third CL in the series, we create the UI layer for the
  KeyguardBottomAreaView and also start using it based on our feature
  flag
- The UI layer contains both the view-models and view-binder that uses
  them
- The KeyguardBottomAreaView class is rigged to use the
  binder/view-model combo instead of its old logic, which is kept intact

Bug: 235403546
Fix: 235403546
Test: Unit tests are included for the view-model only. Also manually
verified that the bottom area behaves as expected with the feature flag
on and with the feature flag off. Specifically:
- The buttons appear at the right times, fade away as you scroll up/down
  and disappear when the device is unlocked
- All three buttons (home controls, quick access wallet, and QR code
  scanner) work when clicked
- The indication area text properly shifts its x/y position to avoid
  pixel burn-in. This is especially visible when moving between AOD and
  lock-screen

Change-Id: Ia2e838d81be2b0f2675efdd10d046e3ed5e79ef1