Add twist-stamper node so nav2 example works with humble

[srmainwaring]

The main addition is to add a twist-stamper node to allow the nav2 example to work with ROS 2 Humble.

See #11 (comment) for details.

Other changes include:

• Update robot base footprint radius.
• Ensure the SDF_PATH env variable is set in launch file to allow robot state publisher to resolve the model (and so TF).
• Display robot model and odometry in rviz.

Dependences

• WIP: Add integration with nav2 #11

[Jagadeesh-pradhani]

Every thing works fine,
Just one thing that, twist_stamped node wasn't working when i ran it with navigation.
Later running it separately worked for me.

[Ryanf55]

The twist stamper is working as intended. Excellent work.

[srmainwaring]

Thanks @ryan, I'll merge once the issue with the failing test is resolved.

Ah, that's an upstream issue with ardupilot_gazebo - missing the gstreamer deps in the cmake. Let me get onto that.