fdo#72276 introduce .uno:ZoomMenu so we can split the menu entries/labels

Currently .uno:zoom is used for the topmenu and submenu.
Deleting the '...' behind the text will delete it for both,
which is not correct. Therefore I introduce .uno:ZoomMenu for the
topmenu.

Change-Id: I75bcae572be0cca7216c34d81e0b99f4c59c0aab
Reviewed-on: https://gerrit.libreoffice.org/8503
Reviewed-by: Maxim Monastirsky <momonasmon@gmail.com>
Tested-by: Maxim Monastirsky <momonasmon@gmail.com>