Add the required infrastructure to support generating multitouch events.

Signed-off-by: Sergio Lopez <slp@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20230526112925.38794-3-slp@redhat.com>