Code review comment for ~raharper/curtin:fix/curtainer-dont-wait-for-snap

I wonder if there's a good reason for seeding the lxd snap in the lxd images given that nested lxd containers do not work, at least not with unprivileged containers.

I'm not against the proposed workaround, but avoiding the need for it would be of course better. What if we switch to minimal images and replace the call to add-apt-repository with dumping a couple of lines to a file in /etc/apt/sources.list.d/? This would make the CI runs even faster, as the minimal images are smaller. One tricky bit is that the ubuntu-minimal LXD remote is not available by default, so curtainer needs to assume a specific configuration is in place - not super nice. What do you think?