Show the status on the status page!

The nominatim server status page at https://nominatim.openstreetmap.org/ui/status.html doesn't actually say anything to affirm the that the service is up and running. There should be a big "All OK" green tick e.g. like on githubstatus.com

It currently looks like this:

I wondered whether some js code was broken because it's also quite weird that...

• The "details" link in the top right does nothing.
• The "API endpoint" link text is a single slash. It should probably be the full absolute path.