This PR adds "The DragonFly Mail Agent (dma)". dma will be the default MTA for a fresh install from r26 on (see r151026 project page). Requirement for mailwrapper will be dropped as it is not necessary on an IPS mediated system (Mailwrapper is still available to support use of packages from non-IPS repositories such as pkgsrc; see also: http://lists.omniti.com/pipermail/omnios-discuss/2015-March/004437.html)

There are now three mediated MTA/MSA packages in OmniOS, dma, sendmail and mailwrapper; only dma is installed by default. To switch between them, install the appropriate package and then configure the mta mediator implementation.

Major parts for patches taken from @daleghent: corecode/dma#39 (comment)

@citrus-it did some testing:

• sending to local users and internet email addresses;
• sending using mailx (e.g. used by nightly.sh);
• FMA mail alerts;
• immediate TLS and STARTTLS;
• CRAM-MD5 AUTH & AUTH LOGIN over TLS.