handle permissions for files, UI changes

Dockerfile

contracts/migrations/0005_alter_contract_notes_and_more.py

contracts/models.py

contracts/templates/contracts/includes/tag.html

contracts/templates/contracts/view_contract.html

contracts/urls.py

contracts/views.py

env.example

registry/settings/base.py

registry/urls.py

requirements/base.txt

users/models.py