Server settings should just be added to the context in build_email, so that
the individual email pathways (and later, the email testing framework)
doesn't have to worry about it.
Previously the rendering code in test_emails.py did not match the rendering
code in send_email.py. This commit removes the duplication to reduce the
chance they drift in the future.
This commit also changes test_emails.html to ensure that we always display
both the HTML and text versions of an email.
This commit replaces all uses of django.core.mail.send_mail with send_email,
other than in the password reset flow, since that code looks like it is just
a patch to Django's password reset code.
The send_email function is in a new file, since putting it in
zerver.lib.notifications would create an import loop with confirmation.models.
send_future_email will soon be moved into email.py as well.
Aditya Ramesh
Rishi Gupta
Vishnu Ks