New Motoman BMDA3 URDF

Files for URDF are included. xacro still needed.
@shaun-edwards: not sure that is really needed: the utility of this file is becoming questionable. Especially in the case of multi group cells and namespacing users will have to update / edit these anyway, and the file isn't used by anything but the launch files we supply in the support packages (the MoveIt configurations by default use their own version of the flle).