ClevoOpenBoardPkg/N1xxWU: Add DSC and build files

Based on KabylakeOpenBoardPkg from the following branch:
https://github.com/tianocore/edk2-platforms/tree/devel-MinPlatform



Adds the DSC and build files necessary to build the N1xxWU Clevo
board instance.

The board follows the same build procedure as other OpenBoardPkg
instances in Platform/Intel in devel-MinPlatform.

Key files
=========
* GitEdk2Clevo.bat - Sets up the local environment for build.
* OpenBoardPkg.dsc - The N1xxWU board description file.
* OpenBoardPkgConfig.dsc - Used for feature-related PCD
  customization.
* OpenBoardPkgPcd.dsc - Used for other PCD customization.
* OpenBoardPkg.fdf - The N1xxWU board flash file.
* FlashMapInclude.fdf - The N1xxWU board flash map.
* cln.bat - Cleans temporary files from the workspace.
* prep.bat - Performs pre-build steps.
* bld.bat - Performs build steps.
* postbuild.bat - Performs post-build steps.
* OpenBoardPkgBuildOption.dsc - Sets build options Based
  on PCD values.

Cc: Hao Wu <hao.a.wu@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Kubacki <michael.a.kubacki@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>