Handle non-rectangle rooms for camera limits

[DarkRewar]

Problem

Currently, the camera limits are set based on the global room size, using min/max positions. This method works for rectangular rooms but not for "freeform".

The method is called in RoomInstance::adjust_camera_limits:

## Adjusts the limits of the given [param camera] to be within this room's rectangular bounds.
func adjust_camera_limits(camera: Camera2D):
	camera.limit_left = 0
	camera.limit_top = 0
	camera.limit_right = get_size().x
	camera.limit_bottom = get_size().y

The following screenshots show how a "L-shape" room applies the camera limits in game :

The room layout:

The room tilemap:

In-game visibility, the camera is correctly confined on the min/max borders, but the camera displays a

Possible solution?

Don't use the native Camera2D::limit_[side] and use a dolly system based on CollisionPolygon2D component? Could be generated on the room_init and confines the camera inside the polygon shape.

[KoBeWi]

You can use get_local_cells() to get room shape and generate a collider.

I think this is out of scope for MetSys, I'd have provide some custom Camera2D script. I tried doing it once and it didn't work well, not sure how it can be implemented.