Automated mailings

[towo]

Fully implement code for automatic accept/eject malis with integration into a ticket system.

[manno]

part of the ticket server integration. frab should contain editable, prefilled text templates for the tickets body

[manno]

Frab has basic ticket server integration (otrs,rt). Ideally one would:

• add a controller to manage text templates (see #59)
• create hooks for a plugin system in frab (see #58)
• turn the old "plain mailer", otrs and rt into seperate plugins (see #57)