Insert `del` commands in order to properly free some memory

[Martyn0324]

• Operating System: Windows 11
• Game: Any
• Backend: GPU (GTX 1650 Ti)

Unfortunately, SerpentAI is a framework that is too expensive computationally when dealing with AIs to the point that upgrading from Windows 10 to Windows 11 makes some Plugins unusable.

One way to avoid this is by using Python's del command after certain steps during training, which will delete the variable from the hardware and free some space.

Also, using a Tree Memory is obscenely expensive. Perhaps there might be some way to avoid that?