Remove arm_id from launchfiles, change franka_control namespacing

CHANGELOG.md

franka_control/config/default_controllers.yaml

franka_control/config/franka_control_node.yaml

franka_control/launch/franka_control.launch

franka_control/src/franka_control_node.cpp

franka_control/src/franka_state_controller.cpp

franka_example_controllers/launch/move_to_start.launch

franka_gripper/config/franka_gripper_node.yaml

franka_gripper/launch/franka_gripper.launch

franka_visualization/launch/franka_visualization.launch

panda_moveit_config/launch/moveit_rviz.launch

panda_moveit_config/launch/panda_moveit.launch