[Gaze] Support Gaze

- Add gaze configs and resources
- Extract the logic for setting/getting gaze out from
  FaceSettingsAttentionPreferenceController to FaceAttentionController

Bug: 388686801
Test: make
Flag: com.android.settings.flags.biometrics_onboarding_education

Change-Id: I2f45c7b01674a28f7f02f614292331ced355cc6f