Add authenticatorId changes to Fingerprint aidl

Also adds a top-level README for the biometric package

Bug: 159667191
Bug: 168541000

Test: make -j56 android.hardware.biometrics.fingerprint-update-api
Test: make -j56 VtsHalBiometricsFingerprintTargetTest

Change-Id: I3dba8e7ee16700865662c1a00b75576d2513f930
diff --git a/biometrics/fingerprint/aidl/default/Session.cpp b/biometrics/fingerprint/aidl/default/Session.cpp
index 5eb3134..a3dd75e 100644
--- a/biometrics/fingerprint/aidl/default/Session.cpp
+++ b/biometrics/fingerprint/aidl/default/Session.cpp
@@ -59,6 +59,11 @@
     return ndk::ScopedAStatus::ok();
 }
 
+ndk::ScopedAStatus Session::invalidateAuthenticatorId(int32_t /*cookie*/,
+                                        const keymaster::HardwareAuthToken& /*hat*/) {
+    return ndk::ScopedAStatus::ok();
+}
+
 ndk::ScopedAStatus Session::resetLockout(int32_t /*cookie*/,
                                          const keymaster::HardwareAuthToken& /*hat*/) {
     return ndk::ScopedAStatus::ok();