Add validator for linked data fields

Fixes EDOZWO-217
Fix routing after importing a resource

Resources are now stored directly after import.
Refactor field definitions
Refactor LinkedDataClient to load RDF without entity
Implement configurable labels for linked data fields

Fixes EDOZWO-218
Implement cache for linked data field labels
Set datastream fields to required

Fixes EDOZWO-207
Fix undefined index for file resources without datastreams
Implement removal of linked data fields

Fixes EDOZWO-210
Refactor loading fields with non-desriptive metadata
Load file size field
Remove unnecessarily thrown exception
Merge pull request #15 from literarymachine/0.1.3

0.1.3