[ FEATURE ] Maintenance page

[imggion]

Is your feature request related to a problem? Please describe

It's just a maintenance page that needs to show up if needed.

Describe the solution you'd like

We are thinking about a static page for now due to our nginx LB that sends traffic to our docker nodes. Using a static page we can configure a route with this logic: if endpointA is down and endpointB is down, send traffic to maintenance page