an improved version of PR #696

The `owncloud` metapackage also installs dependencies such as Apache.
To avoid version problems, just install ownCloud.

- remove configuration of OpenDKIM
- remove OpenDKIM milter from postfix's configuration
- add configuration files for rpsamd's dkim module
- update the rspamd task
- update services in README

- Remove OpenDMARC
- Configure Rspamd for DMARC handling
- Update services and how to set up DNS records in README

resolved issue #721

Sometimes logwatch logs will contain URLs and domain names that trip
on abuse lists.    Use a custom filter to remove these checks.

Password is not necessary when using a trusted
connection (localhost).  Tested by moving mail in and out of Junk
folder while monitoring `/var/log/rspamd/rspamd.log`.

Rmilter [is no longer
needed](https://rspamd.com/doc/quickstart.html#rmilter-setup) as of
Rspamd 1.6.

The configuration file `90-plugin.conf` exists but was not getting
installed.

rmilter fails to start due to a missing trailing semicolon.

there is a missing semicolon that causes rmilter not to start with error:
"config file parse error! line: 156, text: tempdir, reason: syntax error"

which, as expected is the following line

Update for Debian 9

The stock rspamd package provided by Raspbian (jessie) is at version 0.6.10.  The rspamd repository doesn't offer binaries for the armhf architecture (e.g., Raspberry Pi 3) in order to get a more recent package.  Instead, use the yunohost repository for rspamd package (currently at 1.3.5) on armhf.

Implementing password hashing inside password_hash filter plugin

Restart prosody after LE cert renewal

Add group name ssl-cert for SSL certificates

Use postmaster@ for DMARC reports

Switching to Ansible 2

* Install Python 3 pip and cgit dependencies
* Update to cgit 1.1
* Correct Ansible tag syntax for recent versions of Ansible

Avoid opportunity for copy-paste trouble

Also more scriptable, in vein of alternative commands provided

Ensure en_US.UTF-8 locale is present

Update README.md

Correct command line

#626 configure dovecot to move spam to junk folder

Clarifies environments, adds non-passwordless option

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.