2/n: Add default implementation for multi-biometric enroll

1) Adds a layout for multi-biometric selection in BiometricEnrollActivity
2) Adds widgets for checkboxes
3) Shows ConfirmLock*/ChooseLock* for multi-biometric devices in
   BiometricEnrollActivity
4) finish()'s when loses foreground
5) Adds default string for ChooseLock* and multi-biometrics, e.g.
   "Set up Password + Biometrics", as well as associated plumbing
   to bring the user back to BiometricEnrollActivity once the
   credential is enrolled
6) When max templates enrolled, checkbox becomes disabled and
   description string is updated

Bug: 162341940
Bug: 152242790
Fixes: 161742393

No effect on existing devices with the following:
Test: adb shell am start -a android.settings.BIOMETRIC_ENROLL
Test: SUW
Test: make -j RunSettingsRoboTests

Exempt-From-Owner-Approval: Biometric-related change
to EncryptionInterstitial

Change-Id: I855460d50228ace24d4ec5fbe330f02ab406cc02

src/com/android/settings/biometrics/face/FaceEnrollEducation.java

@@ -33,6 +33,7 @@ import android.widget.TextView;
 import com.android.settings.R;
 import com.android.settings.Utils;
 import com.android.settings.biometrics.BiometricEnrollBase;
+import com.android.settings.biometrics.BiometricUtils;
 import com.android.settings.password.ChooseLockSettingsHelper;
 
 import com.google.android.setupcompat.template.FooterBarMixin;
@@ -183,6 +184,7 @@ public class FaceEnrollEducation extends BiometricEnrollBase {
             intent.putExtra(Intent.EXTRA_USER_ID, mUserId);
         }
         intent.putExtra(EXTRA_FROM_SETTINGS_SUMMARY, mFromSettingsSummary);
+        BiometricUtils.copyMultiBiometricExtras(getIntent(), intent);
         final String flattenedString = getString(R.string.config_face_enroll);
         if (!TextUtils.isEmpty(flattenedString)) {
             ComponentName componentName = ComponentName.unflattenFromString(flattenedString);