[Delivers #43561173] Batch creation locations

Backend: a new endpoint and a new function on the Location model to support generation of coordinate data from ranges and creation of subsequent locations.  There's a 'dry run' option, to the user can review the locations that will be created.

Schema: There's a new schema that is used to model the batch request - namely a sub-schema of :location with the range data.

Frontend: A new form "Batch Locations" available to those that can create/modify locations.  Users can enter the ranges, preview the location titles and then create them.

+ unit and selenium tests.