Set storage type for edoweb fields individually

Fixes EDOZWO-141
Fix deprecated API URLs
Load structural metadata from rdf
Improve error handling and logging
Add bundle and fields for file entities
Add custom widget and formatter for datastreams
Refactor file upload

File are not managed by Drupal any longer
Remove superfluous API call

Descriptive and structural metadata is now available from a single URI
Add rdf mapping for field_edoweb_urn
Update entity view

- Add type to entity view
- Show created date at bottom of entity view