Removed submodules and added muzero source code directly

.gitattributes

.gitignore

.gitmodules

LICENSE

README.md

diagnose_model.py

docs/README.md

docs/cartpole-training-summary.png

docs/code-structure-werner-duvaud.png

docs/how-it-works-werner-duvaud.png

docs/lunarlander-training-preview.png

docs/muzero-network-werner-duvaud.png

games/abstract_game.py

games/atari.py

games/breakout.py

games/cartpole.py

games/connect4.py

games/gomoku.py

games/gridworld.py

games/lunarlander.py