Make sure we sleep, even if there are animations. Previously we would
spin the event loop forever once an animation started.
Ideally we need some slint API to get the duration until the next
animation tick.
Define a simple callback to handle touch events from Zephyr. We expect
an input_sdl_touch device to exist in the device tree. This is a fairly
simple implementation as a proof of concept.
The default behaviour of Zephyr (as configured) is to handle inputs in a
separate thread. Each `input_event` describes a specific change, with the
`sync` member specifying when the event has reached a stable state. We
use slint::invoke_from_event_loop to dispatch the slint event in the
main thread.
Add a variant of the printerdemo_mcu that works with Zephyr. For now
we only target the native_sim, and only have rendering set up. Future
commits will add touch support, and investigate synchronization
issues.
