TFC Improved Badlands

This is an addon for [TerraFirmaCraft](https://modrinth.com/mod/terrafirmacraft), that simply changes how badland biomes look and generate in the world. Badland biomes generate like regular in dryer areas, whilst their terrains have changed to be more "normal" towards more humid areas. The more humid terrains assigned to badlands will not have sand or sandstone anymore, and instead have grass, dirt and rocks. The terrain slowly changes into the other, where the "middle point" (50% terrain weight of each other) is at 115 rainfall. When the area is dry enough, sand dunes will start to generate. The threshold values for when the biome terrain should change into dunes or regular badlands are configurable. Adding my other TFC addon [TFC Weather](https://modrinth.com/mod/tfc-weather) allows for more gradual sand slopes, as that mod adds layered sand blocks. This works very well with the sand dunes at lower rainfall levels. Furthermore, the dunes and layered sand fits very well with [TFC Barrens](https://modrinth.com/mod/tfc-barrens), as it completely changes the world to one big desert.