2/n: Refactor out common BiometricService code

Bug: 109900227

Test: fingerprint enrolls (up to 5)
Test: fingerprint authenticates in Settings/Keyguard
Test: removing fingerprints one by one works
Test: removing all fingerprints works
Test: enumerate works (update fingerprintutils to not store in framework)
      "extra fingerprint in hw" situation
Test: enumerate works (update fingerprintutils to store extra in framework)
      "extra fingerprint in framework" situation
Test: launch FP settings, lock screen, auth twice, repeat many times
Test: multi-user - fp for one user does not work for another
Test: multi-user - fp for secondary user works
Test: lockout reset works, per-user
Test: adb shell dumpsys fingerprint
Test: test app works
Test: test app gets automatically canceled when losing foreground
Test: test app without fingerprint/biometric permission is not allowed
Test: manually inspected that each incoming binder call does the heavy
      work on a handler
Test: log tags are per specific biometric for easier log tracking

Change-Id: Id9812e290e6a8098f73cd9902eaca43c02685990