Improve launch files and 3dof simulation

...ple_robot_3dof/launch/kuka_rviz_simulation_3dof_launch.py

...f/launch/kuka_rviz_simulation_3dof_simultaneous_launch.py

ros2_ws/src/simple_robot_3dof/setup.py

..._3dof/simple_robot_3dof/forward_kinematics_node_3dof_1.py

..._3dof/simple_robot_3dof/forward_kinematics_node_3dof_2.py

...imple_robot_3dof/simple_robot_3dof/reference_node_3dof.py