EmulatorPkg/library: RedfishPlatformCredentialLib

EmulatorPkg/library: RedfishPlatformCredentialLib

Platform specific implementation of acquiring credential
to access to Redfish service. This is the platform library
which incorporates with Redfish Credential DXE driver under
Redfish package.

Signed-off-by: Abner Chang <abner.chang@hpe.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Andrew Fish <afish@apple.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Nickle Wang <nickle.wang@hpe.com>
Cc: Peter O'Hanley <peter.ohanley@hpe.com>
Acked-by: Ray Ni <ray.ni@intel.com>