multiple changes for listing events and assemblies

listing actual splittet in list_assemblies.html and list_events.html

• data for events on user schedule, similar to _session_get_favorite_events @grollicus
  • for now, events can only be added to own fahrplan geht jetzt korrekt
• implement in all nedded pages
• use macro functions_buttons in title
• check color theming, bg-assembly working?
• cleanup including fixing components_gallery