Enable django to send emails

[MavropaliasG]

Integrate mail-sending capabilities in Epitome.

This should be started after we finish all the work with the user poll submission feature.

This will allow us to send a mail confirmation on new user registration, and also a weekly digest to users on new polls (future feature).

Refer to https://docs.djangoproject.com/en/2.1/topics/email/

https://simpleisbetterthancomplex.com/tutorial/2016/06/13/how-to-send-email.html