changed the regex; new line at the end is allowed - prevents problems when using cut&paste for the private-key in the interface

skip writing dkim-values for inactive domains
removed the public-dkim-key from the interface
added german language-file

- Added overtraffic notifications to traffic quota system (part of FS#2059 - Extend Traffic quota system)

- replace double-quotes with single-quotes whenever appropriate
- fix indentation

- reword some output
- fix typos

- Updated the user and database prefixes to use this storage.