Add support for messaging to users

[travjenkins]

There are times where we need to make an announcement in the dashboard for users. A recent example was when we had a known issue with stats being calculated. We needed to let know there was an issue.

To keep this simple we'd like to be able to add a basic string to Supabase somewhere and have that show in the UI.

This will probably be something that is pretty important so it will need to be fully visible at all times. This might even be a time where it is okay to push the entire page down? However, that is risk as it can mess with people interacting.