* Writing the additional info_keywords into the episode infos that are passed to the resulst writer. Directly taken from the non-vec version of monitor.
* Added test for monitoring info_keywords.
* Removed unnecessary step of registering the env. Not using make_vec_env, because it applies a monitor wrapper to the env.
* Reformat
Co-authored-by: Antonin Raffin <antonin.raffin@ensta.org>