Refactor the way saving stations works

[starcraft66]

At the moment, when we save the stations, all stations are deleted from the database and re-created. This is unnecessarily destructive imo and results in us saving state about stations in separate tables. As a by-product of this change, we should stop saving the station status in a separate table comprised of many boolean fields and simply make it a field on the station itself.

The new behaviour should simply update station position objects in the database and either prune or create stations based on if the new layout has less or more stations than the current one.

Depends on the merge of #93