UnitTestFrameworkPkg: Add DSC, DSC INC, and YAML files

https://bugzilla.tianocore.org/show_bug.cgi?id=2505



* DSC in root of package file to perform a package
  build of the UnitTestFrameworkPkg and build sample
  unit test for all supported target environments.
* DSC file in Test directory to build the sample
  unit test for the host environment.
* UnitTestFrameworkPkgTarget.dsc.inc - DSC include
  file to !include when building unit tests for
  target environments.
* UnitTestFrameworkPkgHost.dsc.inc - DSC include
  file to !include when building unit tests for
  target environments.
* YAML file with set of CI checks to perform on UnitTestFrameworkPkg.

Cc: Sean Brogan <sean.brogan@microsoft.com>
Cc: Bret Barkelew <Bret.Barkelew@microsoft.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Bret Barkelew <Bret.Barkelew@microsoft.com>
Reviewed-by: Sean Brogan <sean.brogan@microsoft.com>