Make stage complete checkboxes more obvious

[janetriley]

The mark-complete checkboxes are easy to overlook.

I didn't know we were supposed to check them to signal a stage was done, and just checked the URL back in. Judging by other tickets in the pipeline, others are making the same mistake; they have notes about what they harvested but are still open.

Perhaps label the checkbox, or put the checkbox beside the section header.

[kmcculloch]

I think we should add a label at a minimum. We should also emphasize the checkbox in documentation and training.

I've added an issue to discuss other ideas for making the workflow UI more intuitive here: #46

[kmcculloch]

There's a cleanup task in the queue for fixing URLs where the user forgot to check the box: #36

[kmcculloch]

This has been merged to master and deployed