- fixes the language coding: it should be either de_DE or just de;
the latter was chosen because there is only one German
translation and can be used generically. See RFC5646 for the
scheme, ISO 639 for the language part and ISO 3166 for the
territory part.
- Added the translation to the internationalizatio index in
doc/intl/README.md
Removes crosslinking of documentation in favor of a link hierarchy:
- main README.md links to doc/intl/README.md
- doc/intl/README.md links to individual translated documents
This reduces conflicts between translations.