Split crate into shared logic library and binary crate (#52)

crates/shared/src/utils/mod.rs

@@ -0,0 +1,9 @@
+pub mod auto_rotate;
+pub mod billboards;
+pub mod explosions;
+pub mod observers;
+pub mod sprite_3d_animation;
+pub mod squish_animation;
+pub mod trail;
+
+pub(crate) use observers::global_observer;