GUI: status bar rendering. Power: battery indicator. (#207)

* Menu: animation. Irukagotchi: idle image.
* Power: battery, usb activity widget
* Power: tune battery max voltage and clamp overshoot
* get initial charge state

Co-authored-by: Aleksandr Kutuzov <aku@plooks.com>
Co-authored-by: aanper <mail@s3f.ru>

applications/power/power.h

@@ -0,0 +1,3 @@
+#pragma once
+
+typedef struct Power Power;