VDR ports docs

After a quick dis­cus­sion with nox@ I made a copy&paste of his “VDR is com­mit­ted now”-mail into the FreeB­SD wiki. I also re-styled some small parts of it to fit bet­ter into the wiki. It is not per­fect, but already usable. Now inter­est­ed peo­ple can go and improve the docs there.

Thanks to Juer­gen for all his work in this area!