Allow several data files as input

[Nelly-Barret]

For proiding several inputs, we have two ways:

• either specify each filename, separated with commas, as in --data_filepath=datasets/batch/BUZZI/1/screening.csv,datasets/batch/BUZZI/2/screening.csv
• or provide a regular expression to match folders and/or files, as in --data_filepath=datasets/batch/BUZZI/*/screening.csv

The first option seems more controlled as the exact list of files is provided. The second option is shorter to write but the regex can expand to uncontrolled files.

For now, option 1 is more reasonnable (and also considering that this script will be deployed in a real environment).

[Nelly-Barret]

Merged at ea38416e5058bdce1a0bb01747070240be6faaf6