game2d: Add quadtrees for world objects

Author: caseif

engine/modules/game2d/Cargo.toml

@@ -26,6 +26,7 @@ serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true }
 serde_valid = { workspace = true }
 uuid = { workspace = true, features = ["v4"] }
+rstar = "0.11.0"
 
 [build-dependencies]
 argus_build_util = { path = "../../libs/build_util" }