Resolves #363.

Addresses #362.

added dovecot-pop3d
allowed in the firewall
monitored with monit
added relevant tests

Remove all configuration for MySQL and configure PostgreSQL as the main
database.

All *_mysql_* options have been changed to *_db_* options.

Postgres requires the database user to have a password in order to
connect via localhost. The db_admin_password option is used to set the
password of the admin user (usually postgres).

Use the changed `mail_virtual_users` structure to ensure directories and
sieve rules are created for each defined account.

mail_virtual_xx list were not use correctly in tasks.

We got error 'unicode object' has no attribute 'name' because:
with_items:
 - "{{ mail_virtual_xx }}
is understood has a list of strings containing information extracted from {{ mail_virtual_xx }} variable

 Now we use:
   with_items: virtual_domain_xx}}"

These are the changes necessary to enable Roundcube's manage sieve plugin to mange server-side sieve filters.

Signed-off-by: PajamaSoft <support@pajamasoft.com>

Move the settings of the virtual mail directories into a separate
ansible task.

Without the owner being set to vmail and dovecot, when a virtual user
tries to access their mail account, dovecot throws an error that it does
not have permission to create the mail folder for the user.

With the owner and permissions being set the user's mail directory is
created and they can successfully sign in.