Having a separate menu for just one kind of a text box makes
no sense. It isn't good for developers that must remember to
sync changes between the two, and likewise for users which do
customization, and that have to make the same changes twice.

In fact both menus are identical, except that the outlinetext
menu has also .uno:TextAutoFitToSize. But this commands seems
to work also for other kinds of text boxes, and we actually
have a request in tdf#116898 to have it in the context menu.
So we can just move .uno:TextAutoFitToSize to textbox.xml, and
then remove the separate outlinetext.xml.

Fortunately there is no fear of losing existing user
customization for outlinetext.xml, as it wasn't exposed to the
customization dialog by error (no corresponding entries were
added to ImpressWindowState.xcu/DrawWindowState.xcu).

Change-Id: I3568cb95d862d4ab91bedfa691dcc6659a3bf86f
Reviewed-on: https://gerrit.libreoffice.org/61972
Tested-by: Jenkins
Reviewed-by: andreas_kainz <kainz.a@gmail.com>
Reviewed-by: Heiko Tietze <tietze.heiko@gmail.com>