feat: improve data churn

[Szeraax]

When the screen is off, all widgets still refresh on their specified schedule. We should have their refresh intervals use a timestamp. When the screen is off, all refreshes should pause. When the screen is on, resume the refresh schedule, but also refresh and widgets that are now past their scheduled refresh time.

This should also apply to screensaver so that it doesn't continue to access photos or scroll the tabs when the screen is off.