Improve dossier#show load time by x5
This MR only optimizes simply stuff like using db queries instead of loading objects:
- use acccesible_by query instead of retrieving large array of ids
- preload (include) workflows only if needed for query
This could be further improved significantly by using jsonb queries against content item values but this would require more time to get it right (and without risk of introducing bugs).
Closes #1183 (closed)
Edited by Michael Prilop