[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/services/gui/modules/loading.h

@@ -0,0 +1,35 @@
+#pragma once
+#include <gui/view.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Loading anonymous structure */
+typedef struct Loading Loading;
+
+/** Allocate and initialize
+ *
+ * This View used to show system is doing some processing
+ *
+ * @return     Loading View instance
+ */
+Loading* loading_alloc();
+
+/** Deinitialize and free Loading View
+ *
+ * @param      instance  Loading instance
+ */
+void loading_free(Loading* instance);
+
+/** Get Loading view
+ *
+ * @param      instance  Loading instance
+ *
+ * @return     View instance that can be used for embedding
+ */
+View* loading_get_view(Loading* instance);
+
+#ifdef __cplusplus
+}
+#endif