Backup the initial config file?

[valosekj]

The newly added track_corrections function modifies/overwrites the existing YML config file to track which files have been modified.

For example, from the initial config.yml:

FILES_LABEL:
- sub-amuAL_T1w.nii.gz
- sub-amuALT_T1w.nii.gz

To:

CORR_LABEL:
- sub-amuAL_T1w.nii.gz
- sub-amuALT_T1w.nii.gz
FILES_LABEL: []

During #57, we discussed if we want to backup the original config file before modifications, for example as config_backup.yml, see here.

If so, config_backup.yml is not optimal because it would be overwritten every time manual_correction.py starts. I suggest including a timestamp in the filename.