Add Flux automated releases where it makes sense

[mjm]

Flux lets us define rules for automatically updating releases to Docker tags that match a certain pattern. We could use this to automatically deploy releases of new code once the Docker image is pushed. When this happens, Flux commits the change of the release to the Git repo, so we'll even get Slack notifications when this happens.

I imagine a pattern where tagged releases automatically go to production. Staging I'm less sure of. Maybe it could just be every tag, but I'm not sure about that. We may want to define some rules for what gets deployed there, or maybe we keep it manual.

[mjm]

I've added a blanket "deploy everything" pattern for macbot and imaged, so they will always deploy the latest Docker image available. That probably makes sense for those projects, but not really for the others. It's pretty cool to see it work, though!