Siren head

Adds the siren head on Vow and March.

Spawn Config

The spawn is controlled by the Levels config value. Format: "MoonName:Weight;MoonName2:Weight2"

Credits

Model at https://sketchfab.com/3d-models/siren-head-e2a7eca5bc814b6ca5b2d2e85f478360.
Alert sounds from @birdekek and @spinmaster6701 on discord.
Animation from @dotflare on discord.
Step sounds from @spinmaster6701 on discord.
Walkie sounds from @spinmaster6701 on discord.
Terminal entry made by @starstruck1234 and @dotflare on discord.