Delete .gitmodules

.gitmodules

-[submodule "src/franka_description"]
-	path = src/franka_description
-	url = ../franka_description.git
-[submodule "src/panda_moveit_config"]
-	path = src/panda_moveit_config
-	url = ../panda_moveit_config.git
-[submodule "src/panda_simulation"]
-	path = src/panda_simulation
-	url = ../panda_simulation.git
-[submodule "src/sample_applications"]
-	path = src/sample_applications
-	url = ../sample_applications.git
-[submodule "src/panda_teaching"]
-	path = src/panda_teaching
-	url = ../panda_teaching.git
-[submodule "src/zero"]
-	path = src/zero
-	url = ../zero.git
-	branch = master
-