Feature/consolidating edit menu

[acholyn]

closes #434 and #447

The Edit menu has been rejigged to better display options and complete actions without having to require an editing lock. This helps bring more consistency and reduces the code volume.

• Deletion, conversion and duplication are available where relevant without needing a lock and are available when there is a lock
• locking editing is available from the same menu as a dropdown

Below are screengrabs:

(unlinked) fragment without editing lock:

when editing:

testimonia, works and antiquarians when editing:

anonymous without editing lock:

[tcouch]

A few bugs here:

• I couldn't get Delete to work with or without an editing lock in place
• Warnings don't show up for make anonymous/unlinked or duplicate
• If no lock is in place, when you click make anonymous/unlinked you get a message saying you can't because there's no lock

You're not going to be happy with me but I think it might be better if we just have the consolidated 'Actions' menu in edit mode, and keep the original 'Edit' menu for when there isn't a lock.

[acholyn]

I don't think we have any duplication warnings set up
Shall the menu be "edit" as before (when no lock) or still actions > edit

[acholyn]

To do:
change it back so that the options are only available when there's a lock

[acholyn]

need to update so testimonia have the option for duplication and update unlinked with option to convert to testimonium