Added 12 various attestation related vts tests.

- Check for app id only if challenge is provided.
- Verify self sign certificate works for RSA and Ecdsa.
- Verified attestation is generated for encryption keys too.
- Verify no attestation is generated for symetric keys.
- Verify app id is always required when attestation challenge is
  provided to the new key generation.
- Verify app id is ignored when challenge is missing.
- Verify app id length is properly encoded.
- Added vts tests for various attestation success and fail cases.

Test: atest VtsAidlKeyMintTargetTest
Change-Id: If29249b0913fd9c2f91d20188ca5cfbaa04bead8