Setup Nav2 for multirobot simulation

[francocipollone]

🎉 New feature

Closes #64

Summary

• Setup Nav2 for as many robot spawned.
• Flags are added to:
  • enable/disable nav2
  • use other nav2 params
  • select world and map
• Updates README: Some docs and images are changed.

Test it

Read the readme to understand how to run it. However it is simply:

ros2 launch andino_gz andino_gz.launch.py nav2:=True robots:="andino1={x: 0.0, y: 0.0, z: 0.1, yaw: 0.};andino2={x: 1.0, y: 0.0, z: 0.1, yaw: 0.};"

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)

[jballoffet]

This is great, thanks @francocipollone!