Implemented #4561: SHA256 (ECDSAP256SHA256) Algorithm for DNNSEC and Algorithm selector in DNS zone settings.

Some were already in English, most were still in German.

- need to have the pecl idn and intl modules installed
  or
- have the idna_convert class in the classes/idn/ path

Fixed/Implemented: replaced intval() by $app->functions->intval() in all interface functions due to big number problem in intval()

- Implemented: FS#1935 - Add minimum allowed seconds Value for DNS zone records

disable this while I work to clean up the validators, some forms have regex for existing validators. I should add some notes to the Coding Guidelines about this.

Validate DNS notify host. Customers were putting email addresses in there. Testing for IP addresses.

- Changed mbox regex in dns manager.

Added a server module for clients and a mail plugin.