Change RobotUnitModule::Devices to use its own mutexes (also check the RobotUnit's state more often)

Move loading the robot from RobotUnitModule::RobotData::_preOnInitRobotUnit to RobotUnitModule::RobotData::_initVirtualRobot and call this function in RobotUnitModule::ModuleBase::onInitRobotUnit

Change other components to load the robot earlier

Add RobotUnitModules::ControllerManagement::deactivateAndDeleteNJointController (and memberversions for NJointController)

Add versions of {delete,[de]activate}NJointController[s] taking pointers and change code to use them

Also fix some errors due to value return instead of reference return

Refactored the whole RobotUnit (split it in modules, cleaned up code, added doxygen, removed undefined behavior, reduced data sharing)