WIP: Pakon: initial version

This adds documentation for Parental Control. I think the PaKon documentation which was used in our old documentation was documented well. I was thinking if I should document somehow network flows, but I am not sure if it would be understandable.

I re-screenshoted everything. You know, new buttons in LuCI, new graph in Foris. There was some difference between in Czech/English version in Pakon, so I kinda extended it in English version. It is question if we should document and support if somebody wants to remove database, which could be handy if pakon-lists are updated.

Fixes #7 (closed)