The current mouse events are handling events created from both touch
and mouse input. The events have lots of logic to deal with gestures
and different modes (touchpad mode, click-and-drag etc) which are not
applicable for hardware inputs.

Rename the current "mouse events" to "touch events" to clarify which
input that triggered an event. As this is the first commit in multi-
commit change, the mouse input need to use the "touch events" until
a new "mouse event" is implemented.

Add input events that can be used by mouse devices, e.g. mices and
touchpads. This event sends the raw input actions and doesn't care
about different controller modes such as click-and-drag.

Make the mouse controller utilize the new mouse input events.

The delta values are in number of pixels on the native screen
resolution. Need to scale down the delta values based on the
game resolution. Store reminders that are added to next deltas
to mitigate "dead zones" if doing small movements.

Implement support to set the mouse pointer speed in settings.
The mouse pointer speed is applied to both mouse input and touch
input when in touchpad-mode.

Send relative mouse movements from backend for touch events. The
relative x and y values are necessary for some games, e.g. Myst3.

Instead of having duplicated code, utilize the delta mouse function
also for touches when in touchpad mode.