Garbage collector support

[cspotcode]

We must implement explicit support for cpython's garbage collector, otherwise we'll have memory leaks.

https://pyo3.rs/v0.19.0/class/protocols.html?highlight=garbage%20collector#garbage-collector-integration

See this thread where I shared a reproduction which proves we currently have a memory leak:
https://discord.com/channels/458662222697070613/1085299745116917851/1118689518321684541

[Cleptomania]

I'm gonna leave this open because it's probably relevant for future stuff, but as of the 1.0.0 release and stripping out the Sprite stuff which will need to be re-implemented, we don't have anything that this effects, however we definitely will so I'm gonna leave this open as a reminder that we need to do this when the time comes.