investigate avahi cname mappings for local video related machines

[markvdb]

https://github.com/FOSDEM/video/wiki/Avahi-cnames

Just an idea: a random video box (slides, cam, voctop, control) gets its own .local name based upon hostname.

A central point on the network (ansible/web frontend/...) pushes avahi cname mappings for each of these, from box number to room name. Example: cam-janson.local -> cam-17.local, slides-janson.local -> slides-4.local, voctop-janson.local -> voctop-23.local, dump-janson.local -> dump-central.local and/or voctop-23.local.

This looks like it might be a really lightweight way to make the video setup more flexible. Thoughts?