[FL-1884] GPIO application (#732)

* gpio: rename gpio application
* bq25896: add reading OTG config
* furi-hal-power: add is_otg_enabled API
* gpio: introduce new GPIO app, add OTG enable / disable
* variable-item-list: add enter callback
* gpio: add output test view and scene
* gpio app: fix GpioItemTester -> GpioItemTest

Co-authored-by: あく <alleteam@gmail.com>

applications/gpio/gpio_app_i.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include "gpio_app.h"
+#include "gpio_item.h"
+#include "scenes/gpio_scene.h"
+
+#include <gui/gui.h>
+#include <gui/view_dispatcher.h>
+#include <gui/scene_manager.h>
+#include <notification/notification-messages.h>
+
+#include <gui/modules/variable-item-list.h>
+#include "views/gpio_test.h"
+
+struct GpioApp {
+    Gui* gui;
+    ViewDispatcher* view_dispatcher;
+    SceneManager* scene_manager;
+    NotificationApp* notifications;
+
+    VariableItemList* var_item_list;
+    GpioTest* gpio_test;
+};
+
+typedef enum {
+    GpioAppViewVarItemList,
+    GpioAppViewGpioTest,
+} GpioAppView;