Support touch events #36

Currently, applications built with hyprtoolkit (such as hyprland-guiutils) are not very useful on touchscreen-only devices because none of the elements react to touch events.

For most simple things (buttons, sliders, checkboxes), basic parity with mouse clicks would be good.

For advanced things (such as text selection and cursor position), we probably eventually want to design some sensible behavior different from what the mouse/cursor does (magnifying popover? selection handles? some novel idea instead?), but of course, the first step would be making the textboxes selectable.