map, geocode, autocompleter Stimulus refactor from actions to outlets

[nimmolo]

Changes the way map form Stimulus controllers call each other's methods, so that they call the method of the specific controller instance they need. This is necessary for forms where there is more than one autocompleter/map pair on the same page, so that they don't get their signals crossed. Also just seems like better code.

Changes from dispatching JS events, which may be picked up by all controllers on the page (and can only be routed to controllers by type), to calling methods on the controller itself via that controller's outlet identified by a unique id.

Also moves the autocompleter_field helper method and its helpers to a separate file.

[coveralls]

coverage: 93.518%. remained the same
when pulling db417aa on recent-stimulus-changes
into 06aba12 on main.