Reprocess a document from the viewer

[eyeseast]

If I have a document that's stuck in processing or hit some kind of error, I should be able to handle that within the viewer (or maybe search view).

• See a document, even if it hasn't processed (#543)
• See any processing errors
• Have a way to cancel processing if it appears stuck
• Have a way to restart processing

[eyeseast]

Thinking through UX for this:

• We need a button in the Actions sidebar component that opens a modal with reprocessing options.
• If the document is currently processing (or stuck), give an option to cancel and restart.
• If the document has been processed, give options to reprocess.

Reprocessing options include forcing OCR and choosing an OCR engine.