Files can now be auto-saved into a secure folder on the server.
This will prevent people from opening files that do not copmly with
their permissions.

Further, it's now possible to open all types of files in the partner dashboard.

Main points added:
- File Attachments (Agreement only for now)
- Logo to Institution
- Extra ContactTypes
- Subtitle for Contact
- Contact can choose subtitle/kind during activation
- RequestContact
    - Including view/form to submit new request for Partners
    - Including processing view/form for the Admins
- More stuff....

Passwords will be hashed with the Argon2 library.
https://docs.djangoproject.com/en/1.10/topics/auth/passwords/#using-argon2-with-django

Also, new passwords will go through 'common-passwords-checks'. This will prevent
access to accounts using one of those common brute force password hackers around,
in case of a breach.