Add instructions for creating a guest linux

[pingerino]

This PR is ongoing as I do this. I will update as I go. Please let me know if you see something totally wrong!

[lsf37]

@pingerino it looks like there are docs for this now on https://docs.sel4.systems/Tutorials/camkes-vm-linux.html

Can the PR be closed?

[pingerino]

@lsf37 this was specifically for creating the guest linux image. I can't see that in the tutorial?

[lsf37]

@lsf37 this was specifically for creating the guest linux image. I can't see that in the tutorial?

Right, I confused the guest image with the VMM. Sorry about the noise.

[oliver-wm]

@sylGauthier Can you please add to this PR? I think it fits with the current work you're doing :)

[axel-h]

The file has been moved to projects/camkes-arm-vm/index.md, but the content later went to https://github.com/seL4/camkes-arm-vm, which is deprecated by now and https://github.com/seL4/camkes-vm/blob/master/README.md seem a potential new place for such a description one day.