Improve performance of spatial search

[brucecrevensten]

Right now, it takes a few seconds (~5?) to do the place-based search. Fine! But can we do better? How?

[charparr]

Agreed it is kinda slow - and it gets slower each time we add a polygon set.
We might be able to speed this up by implementing in pyGEOS until Shapely 2.0 comes out (see #128 )

[charparr]

Getting closer to being able to try addressing with an updated Shapely! A 2.0 is in pre-release. Following.

[charparr]

Shapely 2.0 is out, if we set the right backend (either pyGEOS or the alternative) we may get a speedup here. This is if we want to retain this approach and not use the WTH-style database approach.

[brucecrevensten]

The faster search is done in Geoserver now, so this ticket can be closed, however there's some work to be done to remove the legacy search code. Tracked in #270