Cache map markers with different filters

Description

Currently (after !3596 (merged)), store map markers are only cached, until a parameter is changed.

Goal

Sets of markers should be cached and reused between changes to the selected store markers.

Links / references

The following discussion from !3596 (merged) should be addressed:

• @alex.simm started a discussion: (+2 comments)

  I think this will make the caching of store markers pretty much useless, because they will be fetched again every time one of the filters is changed. It's not a problem for now because it hasn't been implemented before either, but we should think about a solution later.