prepare internationalisation/localisaton of man-pages

[Markus Hiereth]

Dear FFmpeg-Team,
the Debian maintainer recommended to get in contact with You, see
​https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=986640#10
Best regards
Markus

Original bugreport:

I recently installed ffmpeg and used the manpages in the package as an
introduction. Perhaps, some users of ffmeg would appreciate reading
these manpages in their mother tongue.

A precondition for efficiency in the working field of translation /
localisation, to the texi-files (like ffmpeg.texi) which are precursors
of the manpages, respective message catalogue templates (pot-Files)
should be available.

I've done translations within the German translation team and I am
convinced that I would be able to convert such files from the texi into
the groff format which is accepted by the po4a tools which have
pot-files as output.

But, in any case, internationalisation an localisation are step that
need a common approach of maintainers and translators.