[FL-2627] Flipper applications: SDK, build and debug system (#1387)

* Added support for running applications from SD card (FAPs - Flipper Application Packages)
* Added plugin_dist target for fbt to build FAPs
* All apps of type FlipperAppType.EXTERNAL and FlipperAppType.PLUGIN are built as FAPs by default
* Updated VSCode configuration for new fbt features - re-deploy stock configuration to use them
* Added debugging support for FAPs with fbt debug & VSCode
* Added public firmware API with automated versioning

Co-authored-by: hedger <hedger@users.noreply.github.com>
Co-authored-by: SG <who.just.the.doctor@gmail.com>
Co-authored-by: あく <alleteam@gmail.com>

applications/main/gpio/gpio_app_i.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include "gpio_app.h"
+#include "gpio_item.h"
+#include "scenes/gpio_scene.h"
+#include "gpio_custom_event.h"
+#include "usb_uart_bridge.h"
+
+#include <gui/gui.h>
+#include <gui/view_dispatcher.h>
+#include <gui/scene_manager.h>
+#include <gui/modules/submenu.h>
+#include <notification/notification_messages.h>
+#include <gui/modules/variable_item_list.h>
+#include <gui/modules/widget.h>
+#include "views/gpio_test.h"
+#include "views/gpio_usb_uart.h"
+
+struct GpioApp {
+    Gui* gui;
+    NotificationApp* notifications;
+    ViewDispatcher* view_dispatcher;
+    SceneManager* scene_manager;
+    Widget* widget;
+
+    VariableItemList* var_item_list;
+    GpioTest* gpio_test;
+    GpioUsbUart* gpio_usb_uart;
+    UsbUartBridge* usb_uart_bridge;
+};
+
+typedef enum {
+    GpioAppViewVarItemList,
+    GpioAppViewGpioTest,
+    GpioAppViewUsbUart,
+    GpioAppViewUsbUartCfg,
+    GpioAppViewUsbUartCloseRpc,
+} GpioAppView;