Cache last-updated API call

[mtmail]

For every API call there is a second call to /status to display the last-updated time. It would be nice if the response would be cached, even nominatim.openstreetmap.org doesn't update faster than minutely. Ideally configurable, many installations only once per day.

Displaying "3 minutes ago" (full timestamp when you mouse-over the value) would be great.

[otbutz]

Wouldn't it be better to solve this in the backend by applying fitting cache headers?