Correct command line

It was unclear where do to the commands. Not everyone will know ansible should not be run from the server. Also, the "optional" passwordless option was not actually optional, given how this was written.

- Remove unnecessary dependencies
- Clean up postgresql server setup
- Install from official package repository
- Expect package installer to enable modules that are needed
- Update virtual host config with owncloud 8.2 configuration
- Update post-deploy instructions

Let's Encrypt uses DNS to verify domain ownership, so DNS records must
be set up before the paybook is run the first time.

Make a clean distinction between Debian 7 and Debian 8.  Anticipate the
next Ubuntu LTS release (Xenial) that is planned for support.

I ran a check on http://mail-tester.com and found out I was missing a header to be set for DMARC. SInce I missed it, maybe someone else missed it as well, so maybe it could go into the README.

I ran a check on http://mail-tester.com and found out I was missing a header to be set for DMARC. SInce I missed it, maybe someone else missed it as well, so maybe it could go into the README.

Not awesome. We need a better alternative, ideally one with a better security stance.

Reflects the move to the `sovereign` GitHub organization.

Addresses #361.

Closes #343.