the various part of PlaceEditDialog are unusual in binding multiple things to a
set of shared widgets with a bunch of multiple LINKS to the same things and
using the most recent one shown to displace the previous handlers

End up with multiple notifications in the gtk3 case, rework this to have
a single owner of the widgets so it can do what it wants to do.

Change-Id: I65826a69ce2f1d4279f6e8091a518777fcfeca07
Reviewed-on: https://gerrit.libreoffice.org/54496Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>