Provide two options for barcode tokens on staff slips

The two options should be barcode as an image and barcode as just a number. Currently it's inconsistent.

• For slips, in both preview mode and the actual printed slip, the barcodes render as an image.

Given a staff slip edit/create mode
When operator clicks on the "add token" option { } and the token options are displayed as a modal
Then display two options for user barcode as follows:

• user.barcode (add)
• user.barcodeImage (rename user.barcode to user.barcodeImage)
  And display two options for item barcode as follows:
• item.barcode (add)
• item.barcodeImage (rename item.barcode to item.barcodeImage)

Given a staff slip edit/create or view mode
When operator clicks on "preview"
Then display the user barcode tokens as follows:

• user.barcode as a number only
• user.barcodeImage as a number with a barcode as a single image
  And display the item barcode tokens as follows:
• item.barcode as a number only
• item.barcodeImage as a number with a barcode as a single image

Given a staff slip with reference to user or item barcodes
When printed
Then render the user barcodes as follows:

• user.barcode as a number only
• user.barcodeImage as a number with a barcode as a single image
  And render the item barcode tokens as follows:
• item.barcode as a number only
• item.barcodeImage as a number with a barcode as a single image