[tldoc] tl manual translations

[Karl Berry]

Siep has updated the TL manual with the current state of GUI and Windows
support, plus new screenshots. I think the text is pretty well final by
now, ready for your translation pleasure.

I trivially changed the tex-live.sty for English to center the images
(in PDF mode). Feel free to follow suit or not, as you like.

As usual, for your (w)diff pleasure, the previous year (2018)'s files
are in the archive/ subdir of Master/texmf-dist/doc/texlive/texlive-en/
in the TL tree, aka
http://tug.org/svn/texlive/trunk/Master/texmf-dist/doc/texlive/texlive-en/archive/

Let me know if any questions or problems. --thanks, karl.