WhitleyOpenBoardPkg/SecCore: Add SecCore source code support

Add PlatformSecLib
 so that we can build SecCore.
This uses FSP TempRamInit API in dispatch mode, but directly
tears down NEM as a workaround because the current FSP binaries
do not properly produce the TEMP_RAM_EXIT_PPI.

Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Chasel Chiu <chasel.chiu@intel.com>
Signed-off-by: Isaac Oram <isaac.w.oram@intel.com>
Reviewed-by: Nate DeSimone <nathaniel.l.desimone@intel.com>