The API method Mail.dequeue() should respect SMTP security settings

Current Situation

• The API method Mail.dequeue() uses the default settings to connect to a mail server.
• The properties mail.smtp.user, mail.smtp.password and mail.smtp.port from factory.ini are ignored.

Desired Behavior

• All available settings for SMTP connections should be considered.
• This includes SMTP authentication.

Maintainer Notes

• The current mail interface will be completely re-worked in a future release. Therefore we do not intend to spend time on a minor improvement of a feature that is hardly used by a wider audience.
• This includes development of a plugin that allows to configure mail more easily.
• The stylesheets currently in use for XSLT transformation should be replaced by a more user friendly mechanism.