MdeModulePkg: ReportStatusCodeRouter: Support StandaloneMm RSC Router

MdeModulePkg: ReportStatusCodeRouter: Support StandaloneMm RSC Router

This change added support of RSC router under StandaloneMm. It replaces
SMM version ReportStatusCode protocol definitions with MM version. This
patch also switched to use gMmst instead of gSmst. Lastly, it abstracts
standalone and traditional MM driver entrypoints into separate files to
allow maximal common implementations.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Signed-off-by: Kun Qin <kun.q@outlook.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>