Users are not familiar with term 'banner', so it is replaced with
term 'popup'. Also description has been added to the notifications
and popups switches, which explains why someone might want to disable
popups but leave notifications enabled.
https://bugzilla.gnome.org/show_bug.cgi?id=751369
Place panel switches into GtkListBox and change their
behaviour so that:
When "Notifications" switch is off, all other switches in the dialog are
insensitive.
"Notifications Banners" switch is off and insensitive when corresponding
panel switch is off.
"Show Message Content in Banners" switch is off and insensitive when switch
above is off.
"Lock Screen Notifications" switch is off and insensitive when corresponding
panel switch is off.
"Show Message Content on Lock Screen" switch is off and insensitive when switch
above is off.
https://bugzilla.gnome.org/show_bug.cgi?id=742521
