Begin move mesh + Vertex and Camera into core

src/core/scene.rs

@@ -0,0 +1,21 @@
+use bevy_ecs::world::World;
+
+pub struct Scene {
+    world: World,
+}
+
+impl Scene {
+    pub fn new() -> Self {
+        Self {
+            world: World::new(),
+        }
+    }
+
+    pub fn world(&self) -> &World {
+        &self.world
+    }
+
+    pub fn world_mut(&mut self) -> &mut World {
+        &mut self.world
+    }
+}