Add function that compares UDS Pubs in DICE chains

Adding a test to VtsRemotelyProvisionedComponentTests.cpp that checks
whether the root certificate's public key (UDS_pub) in the DICE chains
for RKP VM ("avf") and the primary KeyMint instance ("default").

Test: m libhwtrust_cxx
      atest libkeymint_remote_prov_support_test

Change-Id: Icbde1d8727f2d1811f9930011059913d84806649