ScenarioManager: auto-discovering all ArmarX packages
This bothered me for a long time ... When (1) creating a new package, (2) setting up a new workspace, (3) working on the robot, you always have to add the ArmarX packages to the Scenario manager. This PR makes this obsolete. ArmarX packages are now automatically detected based on the environment variables.
Much of the code of the scenario manager is now obsolete and can be removed (adding packages is now meaningless).