Removed font declaration from drop downs

Fixed: FS#2593 - PHP Warning: chmod(): No such file or directory in /root/ispconfig3_install/install/dist/lib/debian60.lib.php
Fixed: FS#2595 - postfix RSA certificate generation.
 - Postfix SSL Key is now 4096 bit for greater security

Disabled ipv6 mirror rewriting in this release. This feature is still under development and will get added in 3.0.6

- Adde some missing strings to translations in faq module.

Implemented: FS#2582 - Add support for SSL bundle certificates (SSLCACertificateFile) in ispconfig apache vhost

- Added missing validator for xfer field in dns zone fom

Fixed:  FS#2066 - Check if problems can occur ins ervices when the default prefix is manually changed
 - Notes:
   once the entry was created or modified after applying this update the current prefix is stored with the entry and kept even if the global prefix changes

- Added check that aps plugin installs package only once on a mirrored system
- Added "IPCCommTimeout  7200" in ispconfig apache vhost.

- Changed check if a domain is unique so that vhosts with identical domains/hostnames are allowed on different IPs and/or servers.