Add KeyChainService credential management app APIs

(Trimmed down version)

Bug: 179180345
Test: Manual Testing
      atest com.android.keychain.KeyChainServiceRoboTest

Change-Id: I00b7df27a92f6ee4f74546f892c83290fead1112
Merged-In: I00b7df27a92f6ee4f74546f892c83290fead1112
6 files changed