Some moar features for modding

[GoldenBronze]

Is your feature a UI issue, Quality-of-life, user experience or development issue? If so congrats, you're in the right place!

I hope so.

Is your feature request related to a problem? Please describe.

Yeah, so... my problem is that generifying certain uniques and adding some new ones would help modders like me a lot.

The three features in question are:

1. Making roads and railroads modifyable - currently, these seem hardcoded. Putting their parameters in TileResources.json and allowing Unciv to handle modded roads and railroads would be extremely beneficial for, say, a mod with several kinds of roads.

2. Allowing terrain-tied resources - currently, resources stay the same if a terrain feature (most commonly Forest and Jungle) is removed. I'd like it if it were possible to set a (in TileResources.json) a resource such that it disappears if the terrain feature it occurs on is removed. Admittedly, this is not present in Civ 5 itself, but it would be extremely helpful to modders like me in putting resources like Cedarwood: I mean, you can't get cedarwood from a tile you've deforested, after all!

3. Selective improvement construction: currently, the Roman Legion has the "Can construct roads" unique. It would be great if this unique could be generalised so that it works with any improvement: not only would it make it easy to add the Legion's other ability of constructing forts, it would also be extremely fruitful for modders.

Describe the solution you'd like

1. When described in the json, roads and railroads could have parameters like "Double movement rate" and "Triple movement rate upon researching [ ]". There's lots of opportunity here.

2. A unique for this, maybe "Is removed by [Remove Forest]".

3. "Can construct [Road], [Fort]"

[yairm210]

Please move to #3242