ArmVirtPkg: RMM 1.0-rel0 - Add RPV to RealmConfig

The RMM 1.0-rel0 specification updates the RealmConfig
to add a Realm Personalisation Value (RPV), which is
a 64 byte string that can be used to differentiate or
identify a Realm. The RPV value is provided as an input
parameter to the VMM when launching a Realm.

Therefore, update the RealmConfig structure to add a
new field for the RPV. Also add some helper macros
for defining the RealmConfig structure.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>