Support for Signup

[rubengrill]

It would be great to also have a signup integrated to have a complete authentication process.
As an example, django rest auth has an optional module rest_auth.registration to have a signup additional to login/logout/pw reset/pw change:
https://github.com/Tivix/django-rest-auth/tree/master/rest_auth/registration

The registration has built in support for allauth email verification.

There are some questions regarding this:

1. Does signup need to be optional or should signup always be included (in urls.py). In django rest auth, I think they made it optional because for rest_auth the dependency to allauth is optional whereas for rest_auth.registration it is not.
2. Does signup need email verification? When using the email backend, after logging in the email is indirectly verified by having access to the login code.
3. Should a login code be contained in the signup email, or should a user just do the regular login process afterwards?