Identity Credential: Add some support functions for mDL oem Hal.

Add following crypto APIs to for mDL oem Hal.
ecPrivateKeyToKeyPair()
signEcDsaDigest()
certificateSignedByPublicKey()
coseSignEcDsaWithSignature()
ecdsaSignatureDerToCose()
ecdsaSignatureCoseToDer()
coseSignGetSignature()
coseSignGetAlg()
coseMacWithDigest()
certificateFindPublicKey()
certificateTbsCertificate()
certificateFindSignature()
createAttestationForEcPublicKey()

Bug: 136506289
Test: atest VtsHalIdentityTargetTest
Change-Id: Ib40de4a3ad7e791ff4d82f77292c621653c1a3f3