Cache the task registry results in AMT more efficient

[anneschuth]

Description

The instrument widgets of AMT right now will do a call to the task registry every time that a new page is rendered with the widget in it, this is correct but a little bit slow and just much internet traffic in general. We need to come up with the caching strategy, but also implement it.

If we would cache for a day for example then it could be that the Task Registry is updated and the instruments shown in the overview are outdated, or do we want to have another endpoint in the Task Registry which notifies the user when the state of the instruments applicable has been updated.

Right now this is not a problem for the Requirements widget because that one is heavily mocked, but this would also pose a problem there

Implementation Notes

• warm up on start up (before setting the pod to Ready)
• cache with ttl 1hour
• when the cache is expired, it still returns whatever it has cached and refreshes the cache in the background