EmulatorPkg: Redfish related changes on EmulatorPkg

EmulatorPkg: Redfish related changes on EmulatorPkg

BZ:
https://bugzilla.tianocore.org/show_bug.cgi?id=3102

- REDFISH_ENABLE definition to control EFI Redfish support
- Add Redfish platform host interface library to
  EmulatorPkg build.
- Set RestExServiceDevicePath PCD value.
- Add Redfish host interface config EFI application
  to EmulatorPkg build.
- Use Redfish DSC/FDF include file.

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>