UefiCpuPkg: Add MicrocodeLib for loading microcode

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3303


Signed-off-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>