TR2-3Gold Skyboxes fixed for TEN by Heckler89

Description
This is a pack of skyboxes fixed for TEN

Like TR2 and TR3. Skyboxes from the Gold expansions also have rotation and height issues in TEN so I took the liberty of fixing them to work without scripting

All meshes and textures are ripped directly from legacy TR2Gold and TR3Gold

Note
Credits:
- Core Design
- Hecker89
- The Tomb Engine team