Workdocumentation 2017-09-26

Done

 * 1) moved Wiki to new server
 * 2) as part of the BITPlan wiki farm automatically upgraded to Mediawiki 1.27.3 LTS
 * 3) wiki is now a Semantic MediaWiki e.g. properties like Property:Modification_date are automatically available

Todo

 * 1) check missing extensions
 * 2) use https://www.mediawiki.org/wiki/Extension:MP3MediaHandler as mp3 handler