MdePkg/Include: EFI Redfish Discover protocol

MdePkg/Include: EFI Redfish Discover protocol

Move GUID definition of EFI Redfish Discover protocol
to under MdePkg. With this we don't have dependency of
RedfishPkg in ShellPkg.

Signed-off-by: Abner Chang <abner.chang@hpe.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Cc: Nickle Wang <nickle.wang@hpe.com>
Cc: Peter O'Hanley <peter.ohanley@hpe.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>