sort launch files into subdirectories

launch/cell-controllers/dummy-cell_ads-table.launch

...ell-controllers/dummy-cell_ceti-table-1-placeworld.launch

launch/cell-controllers/dummy-cell_ceti-table-1.launch

...ell-controllers/dummy-cell_ceti-table-2-placeworld.launch

launch/cell-controllers/dummy-cell_ceti-table-2.launch

launch/cell-controllers/dummy-cell_st-table.launch

launch/cell-controllers/gazebo-cell_ads-table.launch

...ll-controllers/gazebo-cell_ceti-table-1-placeworld.launch

launch/cell-controllers/gazebo-cell_ceti-table-1.launch

...ll-controllers/gazebo-cell_ceti-table-2-placeworld.launch

launch/cell-controllers/gazebo-cell_ceti-table-2.launch

launch/cell-controllers/gazebo-cell_st-table.launch

...-controllers/noop-sim-cell_ceti-table-1-emptyworld.launch

...-controllers/noop-sim-cell_ceti-table-1-placeworld.launch

...-controllers/noop-sim-cell_ceti-table-2-placeworld.launch

launch/cell-controllers/robot-cell_ads-table.launch

...ell-controllers/robot-cell_ceti-table-1-emptyworld.launch

...ell-controllers/robot-cell_ceti-table-1-placeworld.launch

launch/cell-controllers/robot-cell_ceti-table-1.launch

...ell-controllers/robot-cell_ceti-table-2-placeworld.launch