Support multiple workflows for creating fields

[taramk]

Currently, creating a field is set up assuming you 1. type the field name and then 2. turn it into a field. Instinctively, I do it the other way around: I know when I'm making it that I want it to be a field, so I make it a field first. When you do this, you end up with a blank field and the cursor moved over to value. It can be a little tedious to move the cursor back over.

If possible, we should support both workflows. If we detect that the field is blank at the time the node is turned into a field, we should keep the cursor in the fieldname input rather than putting it in the value input.