Support logging biometrics onboarding metrics

- Add BiometricsLogger used for logging metrics in
  BiometricsFeatureProvider
- Add OnboardingEvent that represents the SettingsBiometricsOnboarding
  proto message
- Add OnboardingScreenInfoEvent that represents the OnboardingScreenInfo
  prot message

Bug: 370940210
Test: make
Flag: com.android.settings.flags.biometrics_onboarding_education

Change-Id: I9fa6a858c156cae42c1680f51171959f2746fd74