Close citation dialog if user interacts with the integration plugin

[adomasven]

Asks the user if they want to discard the changes in their existing dialog if they have made changes.

If there is no citation dialog, but a command is running (like updating the document) an alert is displayed.

Closes #4855

[adomasven]

I imagine there may be a better way to use fluent here, but given that the form or gender of "document preferences", "citation dialog" and "bibliography dialog" may be different in different languages and require different wording, I split them into different strings.

[dstillman]

I'm getting a communication error from Word while testing this:

1. Click Add/Edit Citation and make a selection, but don't close the dialog.
2. Return to Word and move the cursor elsewhere in the document.
3. Click Add/Edit Citation again.

I get the warning about changes, and then in a second or two Word starts bouncing in my dock (because of the communication-error alert). If I click Cancel — don't discard changes — and then press Return to accept my changes, the progress dialog just hangs, because Word is stuck in the background with the communication-error alert.

[adomasven]

Fixed. Mac Word HTTP communication has some caveats that other plugins don't which is why this was failing. Should be fine on all platforms now.

Also rebased.