!!! WIP !!! squash! Teach mv to update the path entry in .gitmodules for moved submodules

Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
!!! WIP !!! squash! rm: delete .gitmodules entry of submodules removed from the work tree

Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>