Adds the Readme.md file to briefly explain the types of features
supported in the Debugging feature domain directory.
Note that the domain directory is named "Debugging" as opposed to
"Debug" to help indicate that the directory is related to features
used for debugging and it is not an output directory for a Debug
build target.
Cc: Sai Chaganty <rangasai.v.chaganty@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Michael Kubacki <michael.a.kubacki@intel.com>
Reviewed-by: Sai Chaganty <rangasai.v.chaganty@intel.com>
Reviewed-by: Nate DeSimone <nathaniel.l.desimone@intel.com>
