Standardize globbing of input directories

Make all detectors explore recursively the directory given as input

References

Closes #35 (closed)
Notable change: we normalize the csv created by process_raw_output_to_csv so that it is always sorted by key DetectorOutputKeys.img_path, in order to ensure that for a given dataset all detectors output the csv with files in the same order (which was not the case until now).

How to set up and validate locally

poetry run pytest tests/
then open the csv files in folder output at the root of directory. You will see that not only the file "cat.jpg" is processed but also the files "generated/cat_blurred.jpg", "generated/cat_compressed.jpg", etc.