Rural road refactor

[Procyonae]

Summary

None

Purpose of change

Rural/dirt road should use linear ids (which will also allow them to be used for custom connections if I ever get around to making #67736 work)
Rural road and dirt road are very similar other than one using gravel
Rural road forest and dirt road forest are identical to their counterparts other than predecessor but currently redefine the same maps
Less JSON to maintain good

Describe the solution

Uses a special scoped parameter to choose between gravel and soil road
Rural road maps have been removed in favour of the more widely used dirt_road ones
dirt_road and dirt_road_forest ids have been migrated to rural_road and rural_road_forest respectively
rural_road ids have been migrated to linear ids
The maps are all in their own new file because they make up a large amount of farm_lots.json and aren't specific to farms

Describe alternatives you've considered

Some drives and other connections probably want to use nests with the palette to fit nicely with the new parameter but this is already pretty big

Testing

Additional context