new documentation for FRED (available on github)

Hi, in addition to new FRED release, we have also released a new website at https://fred.nic.cz and completely new documentation system. Documentation url is https://fred.nic.cz/documentation. I feel importance of this deserves to use separate email for announcement. New documentation is searchable and it contains many new graphical schemas important to understand FRED architecture and processes. Source code of this documentation in reStructuredText format is available on github   https://github.com/CZ-NIC/fred-docs. This means that you are more then welcomed to submit comments or preferably pull requests for things that you think they are missing in documentation. Please, check documentation and let us know what you think about this. Regards, Jaromir