Removed display of saved collages on the homepage again.

HHNK doesn't want it.
Also removed 'index' from collage storage.

They're not displayed in a list, so an index field is unnecessary
Added db migration
Showing saved collage url in the admin.
Added 'anon_can_store_collage' setting
Added small explanation
Removed is-private check for collage storages
Updated translations
Merge pull request #60 from lizardsystem/reinout-save-dashboard-modifications

Reinout save dashboard modifications