scenes/levels: replace individual managers calling by setManagers

imperium-porcorum.love/scenes/levels/entities/parent.lua

@@ -10,10 +10,8 @@ function Entity:new(world, type, x, y, w, h) -- On enregistre une nouvelle entit
 end
 
 function Entity:initPhysics(world, type, x, y, w, h)
-  self.scene  = world.scene
-  self.world  = world
+  self:setManagers(world)
   self.camera = self.scene.camera
-  self.obj    = self.world.obj
   self.type = type
 
   self.gacc = 550