Improve speed by caching the last few dataview queries

[MaxMoldmann]

Is your feature request related to a problem? Please describe.
My fault with 1500+ notes is loading Dataview queries slower and slower.

Describe the solution you'd like
One potential solution would be #1221 or to cache the results of the last few query runs and then serve them from cache if they are only a few minutes old. Add an option to manually run a query again - in case I added a new note and want it to show up despite the cache.

Describe alternatives you've considered
A more difficult solution would be a cache with an invalidation strategy, where Dataview keeps track of the last few changes in Links or Tags and then only serves a query from the Cache if the entry is not affected by recent changes.