Fix/exercise 4.0 moveit2 motion and planning

This PR addresses the following:

Updated to new Universal Robot Repository (the clone repo part of exercise 3.1 will need to be updated to reflect this)
Uses the FakeInterface in ros2_control to execute trajectories
Modified the myworkcell_and_execution.launch.py launch file to correctly bring up the move_group_node
Implemented MoveItCpp myworkcell_node to plan and execution robot motions with that interface
Moveit Planning Pane in Rviz can be easily added with this configuration TODOs:
Update sphinx documentation for exercise 3.1 (git clone part), 3.4 and 4.0 Instructions to run exercise:
Run moveit_planning_execution (Needed for execution only):
```
ros2 launch myworkcell_moveit_config myworkcell_planning_execution.launch.py
```
NOTE: May need to add all of the visuals in rviz (MoveIt Planning Panel, select "world" frame, Robot Model) the first time

Run workcell launch file

 ros2 launch myworkcell_support workcell.launch.py

ros-industrial / industrial_training