Update styling

  * Change background color
  * Update page title
Cleanup stylesheets

  * GGS is only responsible for updating the grid
  * Move type_sizes styling to importable stylesheet
  * Move playlist specific styling to playlists stylesheet
  * Move reset from GGS to separate reset stylesheet
  * Do not require all stylesheets by default
Cleanup admin view

  * Use common header on all pages
  * Make sure playlist specific styling is contained to just playlists
Update tests

  * Remove useless tests
  * Mark one test to be removed if unnecessary