Integrate with webform workflow module

[patdunlavey]

The webform workflow module adds the ability to add states to webform submissions. Investigate how to integrate this functionality with islandora webform. Some ideas:

• Add filter option to submissions form to only show submissions matching a workflow state.
• Add a configuration on the islandora settings page for the webform to set an "ingestable" workflow state, which would set the default filter for the submissions table.
• Let ingestion automatically change the workflow state (e.g. to "Ingested").