Different arcology layouts based on location

Urban layout (ownership is random):

see #1506 (closed) for more pictures.

All changes only affect new games!

@Pregmodder I will redo the whole arc selection process while I add the layouts to the established arcs.

I tried adding section markers, but there just isn't enough space and just gets too much.

merged

mentioned in commit 8a66e3b3

changed the description

mentioned in issue #1529 (closed)