MdeModulePkg: Connect VariablePolicy business logic to VariableServices

MdeModulePkg: Connect VariablePolicy business logic to VariableServices

https://bugzilla.tianocore.org/show_bug.cgi?id=2522

VariablePolicy is an updated interface to
replace VarLock and VarCheckProtocol.

Add connective code to publish the VariablePolicy protocol
and wire it to either the SMM communication interface
or directly into the VariablePolicyLib business logic.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Bret Barkelew <brbarkel@microsoft.com>
Signed-off-by: Bret Barkelew <brbarkel@microsoft.com>
Reviewed-by: Dandan Bi <dandan.bi@intel.com>
Acked-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>