add ability to convert a note to the registrar to a note to self

Currently a stale note on the Schedule Edits page can either be refreshed (i.e., the date stamp can be updated) or deleted, but could also add the option to convert the note to the registrar to a note to self.

An icon has been added for this already, but the functionality needs to be added.  Can search for: "Convert this note to a note to self" in banner_comparison.html.