Decouple the xacro files

[mhubii]

It would be desirable to replace the iwa7_description.xacro with a iiwa7.urdf.xacro (these would then be compiled by xacro into a raw urdf file), removing all ros2_control related plugins and moving the plugins to the iiwa7.xacro file instead:

1. Includes
   

   lbr_fri_ros2_stack/lbr_description/urdf/iiwa7/iiwa7_description.xacro

   Line 9 in 9125bbc

   <xacro:include filename="$(find lbr_description)/gazebo/lbr_gazebo.xacro" />

2. Macros
   

   lbr_fri_ros2_stack/lbr_description/urdf/iiwa7/iiwa7_description.xacro

   Line 20 in 9125bbc

   <!-- macros for gazebo / mock / hardware -->

Same applies to iiwa14 / med7 / med14.

Briefly running through this procedure highlights the potentially redundant nature of

• initial_joint_positions.yaml
• joint_limits.yaml
• lbr_system_config.yaml

Specifying these limits exclusively in the urdf file might be beneficial.

[mhubii]

The lbr_description is still significantly intertwined with ros2_control. Since this repo currently can't be distributed, this then prevent distribution of lbr_description, e.g. useful for all sorts of downstream usage.

Arguably, the iiwa7.xacro file should live with lbr_ros2_control, whereas the iiwa7.urdf.xacro should live with lbr_description and in an isolated folder (then distributable on ros_distro).

Ideally, the safety_controller should also be removed from the URDF:

lbr_fri_ros2_stack/lbr_description/urdf/iiwa7/iiwa7.urdf.xacro

Line 48 in 37b37d1

<safety_controller

but this would require changes with ros2_control.

[mhubii]

Re-opening because the *.urdf.xacro files currently only specify macros, but don't compile to a URDF..