Split PreOsChecker in a separate file and add minimum APIs
- IsPreOsCheckerLoaded ()
- LoadPreOsChecker ()
- StartPreOsChecker ()
Token space has been changed for PcdPreOsCheckerEnabled
- gPlatformModuleTokenSpaceGuid to gPlatformCommonLibTokenSpaceGuid
- Include/Excluded PreOsChecker according to FeaturePcd
Signed-off-by: Aiden Park <aiden.park@intel.com>