gamepad: expose raw and filtered gamepad events.

[cart]

The latest gamepad event changes made gamepad events have jitter (due to exposing the raw values). This changes that to use the gamepad settings to filter events. We now have GamepadEvent (filtered) and GamepadeEventRaw (unfiltered).

I also renamed gamepad-related types like XSetting to XSettings and made some example changes to improve clarity and terseness.

@simpuid

[simpuid]

As I said earlier, the default values for AxisSettings and ButtonAxisSettings are arbitrary (rest are taken from gilrs). We need to adjust them by testing it.
The current filter function is something like this

However some users may want it like this(no sudden jumps in values)

I am not that much familiar with the functional programming aspect of rust. Maybe we can use a filter lambda or Box<dyn FilterTrait> to support user defined filters.
Or I am thinking too much.

[cart]

Users that don't want the defaults can always change them in the GamepadSettings. For now I think we give adequate control, but I'm open to adding user configured filters to GamepadSettings. Users can also consume GamepadEventRaw directly if they can't make the filtered events work for them (which I doubt).

The main issue that this pr addresses is that the user-facing events don't line up with our high level api, which I consider to be problematic.

[cart]

If we can find better default values thats definitely cool, but thats out of scope for this pr imo