Merge MB_master to main

This merge request aims to simplify the structure of the code by merging 2 functions in "data_process.py" into a single function.

On the "main" branch of the project the "data_process.py" script presently contains: - a function "spectro_extract_valid(data_dir, spectro_dir, events_list)", - a function "spectro_extract_pred(data_dir, spectro_dir)". The main difference between those 2 functions is the "events_list" input and the way this argument is handled. In practical, this is a minor difference that does not justify the use of two devoted functions.

I (mainly) propose in this merge request, a modified version of "data_process.py" that contains a function called "spectro_extract(data_dir, spectro_dir, events_list=None)". The use of a keyword argument which defaults as None, emulate the behavior of the former "spectro_extract_pred()" while the use of a sequence as argument will emulate the behavior of the former "spectro_extract_valid()".

This merge request also remove some unused parameters and function returns (at call).

Mickaël