Add navigation of simulated curio

[knickels]

This PR adds some launchfiles and instructions to allow navigation with the simulated rover.

[srmainwaring]

@knickels thanks for your PR. It's good to have a gmapping / navigation worked example. I've run the example and it works fine.

I've made some edits here: https://github.com/srmainwaring/curio/tree/pr/nickelslab. It's mainly some formatting of the README and moving the image file to the github wiki where I keep the rest of the image files.

If you could merge these changes into your PR and squash the commits I'll merge it into master.

[knickels]

lgtm, marged into the pr. Thanks, @srmainwaring.
You freaked me out a bit, merging my 5 commits while I was away learning how to squash commits in my branch :). I thought for a minute I had somehow written to your repo directly!

[srmainwaring]

Github has an option to squash when merging back into master as well so I thought I'd put it through. Thanks for the addition! I'm trying to use the same workflow as Ardupilot - they have some good notes on using git for their projects here: https://ardupilot.org/dev/docs/git-rebase.html. The gist of it is:

• create a new branch in your fork for work (not master because this can be confusing especially if you've go a number of things on the go).
• rebase your changes on the upstream master quite often
• add lots of small changes but squash everything using interactive rebase when ready for the PR
• you may need to force push to your fork if you are rebasing / squashing

Hope you enjoy the project. I'm working on Ardupilot integration at the moment - I have the simulation running and am now configuring a flight controller on the physical rover. The plan is to replace the Arduino / teensy etc with the FCU and use the RPi4 as a companion computer with ROS. AP has great telemetry, GPS nav and ground station support which I've found hard work in ROS.