OvmfPkg: pull in the SMM IPL and SMM core

OvmfPkg: pull in the SMM IPL and SMM core

"MdeModulePkg/Core/PiSmmCore/PiSmmIpl.inf" (a DXE_RUNTIME_DRIVER)
implements the SMM Initial Program Loader. It produces
EFI_SMM_BASE2_PROTOCOL and EFI_SMM_COMMUNICATION_PROTOCOL, relying on:
- EFI_SMM_ACCESS2_PROTOCOL
  (provided by OvmfPkg/SmmAccess/SmmAccess2Dxe.inf),
- EFI_SMM_CONTROL2_PROTOCOL
  (provided by OvmfPkg/SmmControl2Dxe/SmmControl2Dxe.inf).

(The SMM IPL also depends on EFI_SMM_CONFIGURATION_PROTOCOL_GUID, but this
dependency is not enforced in the entry point. A protocol notify callback
is registered instead, hence we can delay providing that protocol via the
PiSmmCpuDxeSmm driver that is (to be) imported from UefiCpuPkg/.)

The SMM IPL loads the SMM core into SMRAM and executes it from there.
Therefore we add the SMM core to the build as well.

For the SMM core, a number of library classes need to be resolved.
Furthermore, each FDF file must provide the GenFds.py BaseTools utility
with a build rule for SMM_CORE; we copy the DXE_CORE's rule.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19043 6f19259b-4bc3-4df7-8a09-765794883524