Add German subsite

GoGreen should have a German subsite.

Steps to do:

1. add translatable language (see https://wiki.onehippo.com/display/CMS7/Add+a+translatable+language)

2. translate (some of) the content in the CMS. Don't forget to translate the meta-data of documents too (like tags).
to easily reuse HST configuration, it's best to NOT translate the 'comments' folder in the CMS.

3. in the source code, translate the labels used in the site. Located in:

• site/src/main/resources/META-INF/messages_<locale>.properties
• site/src/main/resources/META-INF/typenames_<locale>.properties

4. translate the sitemap and sitemenus, located in:

• content/src/main/resources/hst/configurations/<sitename>/sitemap.xml
• content/src/main/resources/hst/configurations/<sitename>/sitemenus.xml
  (Create new files for each added language, and add the right initialize items to hippoecm-extension.xml).

5. add the HST component configuration for each language and correct all paths to translated content, e.g. the paths to the banners shown at the home page

6. translate the labels in the faceted navigation nodes (copy them from the english content folders). These are located in the repository in the property 'facetnodenames' at

• /content/documents/<hipposomething>/<news>/facetednews
• /content/documents/<hipposomething>/<products>/facetedproducts
• /content/documents/<hipposomething>/jobfacets
• /content/documents/<hipposomething>/searchfacets

7. add a domain rule to allow the addition of comments and reviews in the translated content trees
Check that adding a comment to a news article and event and adding a product review in the translated subsite still works correctly.