Remove user contributions when archiving a project

[Hagellach37]

When a projects status is set to archive the back end workers should also remove all user contributions for this project.

The user contributions are either stored under:

• v2/users/{user_id}/contributions/{project_id}

This will help to reduce storage and download in Firebase.

[gcaria]

Hi, I'm trying to understand how to address this issue.

Should the change take place in mapswipe_workers/mapswipe_workers/firebase_to_postgres/archive_project.py ?