New env support:

• Isaac Lab (Add support for special VecEnv (brax, IsaacSim, ...) #484)
  - [ ] Env Pool ([Feature Request] Integrate EnvPool #241) no longer maintained
• Brax envs (Add support for special VecEnv (brax, IsaacSim, ...) #484)
• DM Control (see https://gist.github.com/araffin/534f7f1506364eb824c2f4d6a2dd81d1)

Improvements:

• Allow to save stats with checkpoints / best model stats ([question] All checkpoints use the same VecNormalize statistics #278)
• Improve test coverage
• Add low pass filter wrapper (https://github.com/ikostrikov/walk_in_the_park/blob/ee345db217f9d7392963a76c93dc186474075f80/filter.py)
• Improve hyperparameter optimization + stand alone (as for cleanrl): ([Enhancement] Support copying optuna params dict for all hyperparameters #121)
• Move documentation to read the docs?
• allow python file for passing hyperparameters? See Allow python script for hyperparameter configuration #318