create rviz plugin

[rhaschke]

Create an rviz::Panel plugin to configure (and test) a CBF controller.

The Panel should create its own rviz::Display showing the following rviz::Properties in the displays tree:

• robot_description
• group (defines the to-be-used kinematic tree)

The Panel essentially contains a TreeView showing the hierarchy of controllers with its properties. Eventually, the properties should go into a separate TreeView?

The following controllers are possible:

• Position (SquarePotential): link, tolerances
• Orientation (AxisAnglePotential): link, tolerances
• Joints (SquarePotential): tolerances

these are possible operators

• Composite (any)
• Pose = Composite (Position, Orientation)
• Diff (Position / Orientation)
• Distance (Position)

general properties:

• solver
• convergence criteria

consider reusing MoveIt's:

• RobotInteraction for marker display (will need heavy adaption -> copy and adapt)
• RobotStateVisualization for robot visualization

[rhaschke]

Start with the simple fixed controller we already have and try to display its properties in the TreeView. Even before, setup the infrastructure, showing the Panel, creating the Display and markers, etc. That is, turn our toy program into an rviz plugin.