Make Journal selection optional for submission workflow

[markpatton]

The initial workflow step should be modified such that the journal does not need to be entered. A message should be added encouraging the journal to be entered if possible.

The Policy step needs to be modified such that it handles the case of no journal being present.

The Detail step should be modified to require the user to go back and enter the journal if required by one of the selected repositories. This is determined by examining if journal-title is in the required block of the json schema returned by the metadata schema service.