Silicon/Tools: Add a tool FitGen

The utility of this tool is part of build process for IA32/X64 FD.
It generates FIT table.
https://bugzilla.tianocore.org/show_bug.cgi?id=1849



Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>