A list of "user applications" is built at compile time. It contains all the info needed to create the application at runtime (ptr to a create() function) and to display the app in the application menu. All applications declare a TypeTrait with these information.
When a new app must be loaded, DisplayApp first check if this app is a System app (in which case it creates it like it did before). If it's not a System app, it looks for the app in the list of User applications and creates it if it found it.
Those changes allow to more easily add new app and to select which app must be built into the firmware.
Switch to C++20 (and fix a few issues in SpiMaster.cpp and Watchdog.cpp.
* Reset timer by long pressing on the button
* Consider press_lost as released
Otherwise the bar would keep increasing if the finger slid off the
button
When the screen switches, the full screen needs to be refreshed for the
hardware scrolling to work. This was enforced with backgroundLabels, but
is simpler to do with a rounder function.
Don't use relative imports like `../foo.h` as those depend on the
relative position of both files. Rather than that use imports relative
to the `src` directory, which explicitly is part of the include
directories.
* built timer app
* Style improvements
* making sure buttons stay hidden when the app is reopened and reappear after the timer runs out
* more sensible calculations of time deltas. eliminated that mysterious scaling factor
* changing the timer icon
