conf: rename to 70-synaptics.conf

Bump up the synaptics driver to 70, so it get's preferred over libinput, which
was dropped down to 60. The synaptics driver is more of a leaf package
than libinput (which covers a multitude of device types) and can be removed by
default. When specifically installed by the user, the synaptics driver should
override the system default.

Similar to what was done for wacom configuration file.

https://bugzilla.suse.com/show_bug.cgi?id=979554



Signed-off-by: Stefan Dirsch <sndirsch@suse.de>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>