* Improve german HOWTO file by fixing some grammar and restructuring some sentences to make it easier to read and understand
* Improve german CONTRIBUTING file by fixing some grammar and fix some readability issues
* Added a non-breaking space for "z. B." to prevent automatic line break
* Restore alignment on good/bad examples with colons
* add CONTRIBUTING-de.md with German contributing guidelines.
* edit typos in CONTRIBUTING.md.
* add link to German contributing guide to language list in other contribution files, re-order list alphabetically.
* switch back the order of English and French language links in all Contribution Guidelines.
* eliminate extra spaces and put spaces in the correct positions.