Feature request: Add new categories from the transcription-category list

[psully]

One thing I'm running into from time to time is that when I'm transcribing a page (as an admin), I will want to add new categories as they come up. So after saving a page, the categories list appears, but if I want to add to the list, I generally open a new browser tab, navigate to the collection/categories area, add the new category, then either refresh or go back and try again.

It would be much easier if admin or editors could add categories on-the-spot.

[benwbrum]

That's a great idea -- I'll make it so that admins and work owners can add categories.

[benwbrum]

Done!