Robotnik Car common packages

It contains the urdf, meshes, and other elements needed in the description are contained here.

##rbcar_pad This package allows controlling the robot using a joystick or game-pad, by sending the messages received through the joystick input, correctly adapted, to the correct command topic.

Ackermann drive controller: included in the directory rbcar_common/rbcar_control/lib/ Robotnik msgs: included in the directory rbcar_common/rbcar_control/lib/