Use GitHub artifacts for glimesh.tv deploy

[clone1018]

We are now building an artifact for every GitHub push to dev, it would be nice to sue this pre-built image to run our production servers (instead of building a fresh copy on each server). This would also allow us to digest our assets once (if we wanted to use a CDN).

https://github.com/Glimesh/glimesh.tv/actions/runs/758622405#artifacts

[LukeHandle]

Main hurdle for using the GitHub artifacts is the requirement for auth so that you can download them, eg. https://github.com/Glimesh/glimesh.tv/suites/2648054351/artifacts/58185635 is a 404 when not authed (try Incognito).

If instead proper releases were created, these would be handier. For dev builds, adding the git short hash to the version would also make sense for a release - and is a step we already take.