doc: remove old translations

For no_NO.ISO8859-1:

The Last Changed Date of no_NO was on 2013-11-07 16:37:11 +0000 (Thu,
07 Nov 2013). Of all the file, only the handbook has any translations
of which there are only basics/chapter.xml, bibliography/chapter.xml,
and install/chapter.xml. The latter of which still documents
sysinstall. I also can't seem to find any reference to the files
here: https://download.freebsd.org/ftp/doc/.

For sr_YU.ISO8859-2: no content in-tree at all.

Discussed with: blackend