tests/krb5: Add RodcPacEncryptionKey type allowing for RODC PAC signatures

tests/krb5: Add RodcPacEncryptionKey type allowing for RODC PAC signatures

Signatures created by an RODC have an RODCIdentifier appended to them
identifying the RODC's krbtgt account.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14642

Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Isaac Boukris <iboukris@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Tue Sep 21 23:55:39 UTC 2021 on sn-devel-184