Pre-installed Ubuntu and Arch desktop images for LXD

TLDR for those who don't want to watch the video!

We've started building daily images of some Linux distributions' desktop environments. Those run using LXD VMs and get you functional desktop environment already setup with user account and all. No install or setup needed, great to try other distros.

Currently got Arch and Ubuntu available, Fedora should follow soon, then we'll go based on demand.