install-local: Make configurable and limit depth-search

Only look for mgwport packages in the direct subfolders, otherwise
we also install the packages in the mgwport folder dist twice.

Use command line arguments to specify the source paths.

Signed-off-by: Thomas Braun <thomas.braun@virtuell-zuhause.de>
Merge pull request #1 from t-b/enhance-install-local

Make configurable and limit depth-search