Power subsystem improvements and bug fixes (#353)

* BT: render icon statically.
* Move API HAL Power init call to api_hal_init.
* API HAL Power: replace stop2 mode with stop1 to ensure usb and lptim2 proper work.

applications/bt/bt_i.h

@@ -18,7 +18,6 @@ typedef struct {
     Gui* gui;
     ValueMutex* menu;
     // Status bar
-    Icon* statusbar_icon;
     ViewPort* statusbar_view_port;
     // Menu
     Icon* menu_icon;