Refactor KeyChainService authorization checks

* Add precondition check and callerIdentity
* Allow credential management app to call
  removeCredentialManagementApp and
  removeKeyPair

Bug: 177979648
Test: CTSVerifier CredentialManagementAppActivity
      atest android.keystore.cts.KeyChainTest
      atest com.android.cts.devicepolicy.MixedDeviceOwnerTest#testKeyManagement
      atest com.android.cts.devicepolicy.MixedDeviceOwnerTest#testDelegationCertSelection
      atest android.devicepolicy.cts.CredentialManagementAppTest

Change-Id: I4730de49bba20b3bca533074af6a5e9cbc69e6de
1 file changed