Enable remaining file upload / document tests again
For #477 (closed) and for #458 (closed)
Several file_upload or document tests were set to "skipped". These should be refactored and enabled again.
- Refactor last skipped file_upload test to model search_test (file upload via UI is covered by search_system_test)
- Enable last task controller tests to handle documente (create, update, delete)
Edited by Michael Prilop