Add start of german translation

This is a gettextization of https://repo.or.cz/gitman-de.git. Need review

create_po4a_conf.sh

 #!/bin/bash
 
 (cat <<EOF
-[po4a_langs] fr
+[po4a_langs] fr de
 [po4a_paths] po/documentation.pot \$lang:po/documentation.\$lang.po
 [options] opt: " -k 80"