More Terrain Options in Map Editor

More Map Editor Options needed.

I am in the middle of working on an "island flipper" map with the map editor, a map that was used as illegal garbage dumping site for an eternity. I am lacking some options to properly do so.

I would like to be able to create the following:

- Reservoir of wastewater, sour water and the like
- All usual terrain options being able to select scrap metal, scrap copper, unsorted scrap, and the like. I am aware that those cannot be dumped as of now, which I like to consider as a bug.
- A noise function that can be applied using certain materials (e.g. dirt) in a later step. Used for adding patches of dirt to a garbage pile that has been sitting there for ages (although that might already exist, I probably just didn't look close enough).