Platform independent UI code

The UI core itself now does not depend on ESP code. It is generic process.

The application and UI user side now handle initialization UART interface. This was necessary step in order to allow make UI core independent on interface.

The UI core does not work as RTOS task. It is up to upper layer how ofter will poll UI core service. This also remove dependency to RTOS. Add function which conver error code for UI core to string.

Removed "factory settings" hidden command. There are other ways how to do it, plus it brings some inconsistency into program logic.

Remove reboot command as well, since it is platform dependent. Leaving this command up to UI user part.

Removed logs from UI core. This would bring unnecessary complexity and core is quite tested, so actually not much needed anyways.