No Cliff 3d Assets

[cjamierun]

While creating the missing terrain for the Forest Zone, it was determined that 3d cliff assets were required.

3 different cliff models, should be enough, since they can then be bundled into various clusters.

• [x] Cliff 1
• [x] Cliff 2
• [x] Cliff 3

[cjamierun]

Cliff 1 completed

[cjamierun]

Cliffs 2 and 3 completed, as well as clusters 1, 2, 3, and mixed clusters 1, 2, and 3.

[cjamierun]

Retexturing cliffs using new gradient technique.

[cjamierun]

Cliffs tested in Godot, looks good.