clear region naming & showing

[bvreede]

The region options are named with acronyms, which can be confusing as it is not explicitly shown which region is called what in the leaflet map.
It would also help to have a border on the region when it is selected.

[sverhoeven]

Also the region name is rendered as select form field with a single option. As you can not change it and you can only have one region selected it would be nicer to render it as non-interactive text.