refs #15208 [fid_bbi] footer

* add FAQ for BBI
** overwrite translations for FAQ
** add texts for faq in German and English
** implement language switch in content.phtml
* add 'about us' and refactor faq
** add about-us for German and Englsh
** modify layout for faq
** rename German faq from faq-de to faq - as default
* hide Contact details temporarily and set translation for terms of use
* change translation for Privacy Policy