Support for Screens with Content and Campaigns

[cooperj]

Need to replace what we have with Screenly OSE at the moment. We basically need an easy way to upload content and show it on the TVs it would then be very useful to have a way to build campaigns for things such as YSWD or CSS etc.

A campaign should be a way of uploading content to a group of carousels (displays).

Each carousel has its own content pipeline (i.e. for things such as timetables) and then adds in access to campaigns.
There should then be a sql join which basically just gives us one huge list of content, the Yggdrasil devices can then download and manage this as required.

It has also been requested that we can support streaming video with RTSP from the lab cams. This might not be doable as the cams have a limit of how many devices can stream from them… but we could always fall back to the mjpeg stream via the proxy app (as we do for grafana)

Screens should shutdown over night
Screens should have functionality to be taken over for alerts. (i.e. tech office when wall needs opening)

This will likely have further implications on the Yggdrasil project.