Add a "replace" operation for single-value reference fields

Problem/Motivation

If I, as a user, want to replace the currently referenced entity, it is currently a two-step process. I need to remove the current entity, and then add a reference to a different entity. I would prefer to do this in a single step.

Proposed resolution

Allow the site builder to make available a new "replace" operation that when click would take the user directly to the step of choosing a different entity. Theoretically we could also have a "replace with new" option.