Remove the GenerateRkpKey service

With the move to rkpd, we no longer need to make calls from framework
into the remote provisioner to tell it that a key was consumed.

Bug: 274823784
Test: atest KeystoreTests
Test: atest CtsKeystoreTestCases:android.keystore.cts.KeyAttestationTest
Change-Id: I510d471a980c62e5798e459729f73c231321d2a9