January Update

[simoninithomas]

This update solves or merge:

• unit3 | deep-q-algorithm | catastrophic forgetting #437
• Update role assignment channel #458
• Super tiny fix typo #455
• Arrow showing wrong direction to take for step #456
• pyvirtualdisplay not visible [HANDS-ON BUG] #453
• [UPDATE] Potentially incorrect terminology in unit 2 midway recap #451
• Small typo correction on the Godot-RL section #448
• This PR solves issue #434 #445
• [HANDS-ON BUG] #434
• [UPDATE]TYPO: Bonus Unit 1 - ML agents parameters #443
• Update train.mdx : this commit fixes #443 #444