[Tails-l10n] [Review](de) wiki translation for download page

Hi,

Please review branch nivatius-download

3544740 (de) wiki download page: review by flapflap
cfacb37 (de) wiki download page: poedit file header
9e0c797 Merge branch 'master' into nivatius-download
d69bb27 (de) wiki download page: some minor fixes
a7429cc (de) wiki download page: poedit header update (nivatius)
62e384f (de) wiki download page: lots of translated strings (nivatius)
a0815be (de) wiki download page: use formal 'Sie' instead of 'du' (nivatius)
d1663c2 (de) wiki translation for download page, minor fixes
4bebd7a (de) wiki translation for download page from nivatius

in flapflap/tailsxlat.git

nivatius translated the download page exhaustively, and I already added
my review on top, and it looks quite well to me.
Nonetheless, I'd like someone to review it, because it's the download
page and everyone will read it...

The download page is very long, so it'll surly take some time for the
reviewer...

~flapflap

PS: I also found a broken link on all languages (points to external
documentation, not so important); will file a ticket once the branch is
merged and a patch to fix the link