Update to Ubuntu 20.04 and Gazebo 11

[julianoes]

Anything newer will have to be new Gazebo.

Instead of #53

[JonasVautherin]

Thanks!

I already have a branch for new gazebo: https://github.com/JonasVautherin/px4-gazebo-headless/tree/add-gz-harmonic

But it has fewer features (the video streaming doesn't exist there), so it didn't seem worth updating.

[julianoes]

Nice!

I think video streaming is coming there soon. I think @dakejahl mentioned something.

[dakejahl]

Yeah I added (Claude added) a gstreamer plugin for new gazebo.
PX4/PX4-Autopilot#24475

As far as missing features go, we have an issue tracker here
PX4/PX4-Autopilot#23602

but I think some of the items in the list are non-essential (boats, catapult launch, etc). Maybe you guys can comment on what is essential vs what is nice to have? IMO the essential features should have accompanying CI tests

[JonasVautherin]

Oh nice! So yeah, maybe it will soon be time to move to new gazebo here!

[JonasVautherin]

For the record, master is now on gazebo-harmonic 🙌 .