Merge branch 'master' into phpunit8

Merge branch 'master' into phpunit8

* master:
  dwpage: output meta data as JSON
  dwpage: rename gmeta into getmeta
  translation update
  Make it easier to remove h1 around logo
  fix: better max-width for images in tables
  dwpage.php: add an option to get metadata
  rename namespace Media to File
  use SVG icons for media file links
  readded $jump mechanism, removed unused functions
  fix use of $rev parameter
  fix entity definition
  reenable the option to display a relative namespace for media files
  simplified the media_searchlist tests
  make use of the new media file classes
  SVG based file icons
  first go a refactoring the media manager
  lazy load images