Replace authentication system

[mcab]

Turns out, DRF tokens don't scale too well.

Looking for a better solution.

[mcab]

Resources:

• django-rest-knox for better support on using multiple devices.
• django-allauth to provide a better system for authentication, registration, and account management, with a side effect of adding social logins.
• django-rest-auth to see how authentication over REST API can work (especially for SPAs).
• django-rest-registration, similar to above.
• django-rest-social-auth + knox for social authentication.
• social-core as a means for social logins.
• django-axes for login abuse prevention.