Improve road generation

[freeborough]

Currently the roads are created very simply (cross-roads only!) therefore we need to do something more, otherwise a core part of gameplay (navigating the world) is going to be boring.

[freeborough]

I was thinking we could create chunks that have defined road connection points, like the road tiles with straights, bends, intersections, and cross-roads. What occurs within the chunk doesn't matter, only that those connection 'agreements' are met.

We could then use something more complex to generate the roads within the chunks, for example L-systems look like they might be a good fit and produce interesting yet not entirely chaotic results.

We could then use another algorithm to decide which type of chunk(s) we're going to be placing. Something like a walker or wave collapse function might be appropriate here. The main caveat is that it can't fail (we don't want to be re-generating large chunks of the city), so such algorithms would need to be designed with that in mind.