Support the ability to put up a temporary message to users on the home page to alert them to current problems, upcoming outages, etc. Something an SDR admin could do by altering a resource without the need for deployment/restart or other developer/devOps involvement.

This has been discussed in the past as a need for a general facility for potentially any of our apps, particularly those where processing is involved -- Hydrus availability issues, ETDs, Mirador -- but also as a means to make announcements about, say, important new features.