MdeModulePkg/metafile: Add PCD PcdCpuStackGuard

MdeModulePkg/metafile: Add PCD PcdCpuStackGuard

PcdCpuStackGuard is introduced to enable/disable Stack Guard feature.
Its value is FALSE by default. This feature is suggested to be enabled
only if the cpu driver and CpuExceptionHandlerLib have supported stack
switch for the processor used in platform. Otherwise the exception dump
message won't be printed out when there's a stack overflow happened.

Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Suggested-by: Ayellet Wolman <ayellet.wolman@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Jeff Fan <vanjeff_919@hotmail.com>
Reviewed-by: Jiewen.yao@intel.com