Refactor geospatial_search_helper.rb

This gets rid of a ton of code which has been copy-pasted merely to change a line or two, seriously violating D.R.Y. Code from two prominant functions, `initialize_geospatial_dashboard` and `geospatial_search_ajax` are merged into one common function `geoospatial_init(context)`. The original two functions now simply call the common function with a different `context` symbol.
Nothing should change from the frontend side of things except maybe speed improvements.
There's more that can be done here, e.g. bounding box calculations, searches, but I see no immediate need to refactor to that level with the other projects in Pivotal triage.
This branch should be ready for fast-forward merge.