[font selector] don't reopen document just use ConfigInterface instead.

>> > Lol, you are closing and opening the document, seems a bit extreme
>> > :D
>>
>> I did this because we need do update all pages. So why not?
>> But it was is a _hack_. Can you suggest better decision?
>
> Sure, have a look at PDFGenerator::reparseConfig for example.
[font selector] drop unsed m_font from private document
[font selector] drop etra header from document.cpp - QFont