Login message to users from tenant owner

[simondate]

It would be nice if a tenant owner could leave a message for their tenant users either when they login or even shown above the list of courses. Imagine something like a IRC client's welcome message :neckbeard:

This message could contain tips on how to use Adapt and any links to any documentation needed. There could also be a section from the Adapt team with the latest release version notes.

[taylortom]

I like this idea

[lc-thomasberger]

Very nice idea, but i think it should be more generic. Thinking of something like a user notification system. So that users can send messages / notifications to each other.