Winterize Terrain

Turns terrains into winter landscapes and adds snowy weather.
Feel free to make pull requests if you want additional overrides for materials in your own terrains.

Feedback tracker: https://github.com/Kexanone/ArmaReforgerMods/issues
Source Code: https://github.com/Kexanone/ArmaReforgerMods/tree/main/addons/WinterizeTerrain

WARNINGS:
- Make sure to load any terrain mod before this mod or it may produce a crash.

Acknowledgments:
- Snowy weather presets were copied from BI's C&H - Snowball Fight 2023 mod (https://reforger.armaplatform.com/workshop/5F02BE2E93634E0A-C%2526H-SnowballFight2023)
- The snow texture was created by Brian, owner of "Free PBR" (https://freepbr.com/about-free-pbr/)
- Thanks to KIOK for the tips on retexturing rocks.