Revamp gamepad input mapping #756

The gamepad input mapping was done very long time ago and it seems that things have changed in the way OS handles gamepad.

For linux, everything seems to be mapped the same, ie. everything looks like an xbox controller. I suspect the same is true for Mac and Windows.

This means that we might be able to simplify a lot the mapping: we should be able to know what is the left and right thumbstick for example, so instead of having this very generic mapping we have now, we can just expose mode 1,2,3,4 and allow the user to map thumbsticks to Crazyflie commands. There is of course a difficulty that we might still want to allow fully custom mapping. Maybe this can be done in two layer though: first map axis to a standard gamepad, this would be automatic unless the user wants to make a custom gamepad. And then map the standard gamepad to Crazyflies commands.

At the very least, the current list of preset should be fixed: it does not match reality anymore.