BibWorkflow: workflow model changes

• Renames WfeObject to BibWorkflowObject and changes the way these are created - now with strict dictionary format for API functions.

• Fixes display of modal windows for workflow and objects details.

• Moves JavaScript to separate files.

• Adds MIME type evaluation function.

• Changes data structure in a few places (e.g. new URI field).

• Fixes tests for new data structure.

• Adds database logging for workflow engine.

• Improves Celery worker plugin.

• Fixes import of WfeObject in WebDeposit. Changed to BibWorkflowObject.

Tested-by: Jan Aage Lavik <jan.age.lavik@cern.ch>