Moodle bulk download and upload

Submissions can be downloaded and feedback uploaded in bulk as a zip file.

The downloaded zip file either contains per-participant folders, or a flat collection of files, depending on the option Download submissions in folders.

Folders structure:

Participant_100001_assignsubmission_file/
  script.m
  document.pdf
Participant_100002_assignsubmission_file/
  text.txt
  special script.m
  explanation.docx

Flat structure:

Participant_100001_assignsubmission_file_script.m
Participant_100001_assignsubmission_file_document.pdf
Participant_100002_assignsubmission_file_text.txt
Participant_100002_assignsubmission_file_special script.m
Participant_100002_assignsubmission_file_explanation.docx

Feedback files can be uploaded in either form.