adding basics of ds4 controller, no status or connections or l3/r3

Adding the basics of the ds4 controller, more to come hopefully once we get this [issue](https://github.com/lukekarrys/hid-mapper/issues/4) in hid-mapper gets looked at more - this gives all buttons and joysticks other than l3 and r3. The ds3 outputs connection statuses etc, hopefully we can get that out of the ds4 too.