[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>

lib/flipper_application/flipper_application.h

@@ -0,0 +1,129 @@
+#pragma once
+
+#include "application_manifest.h"
+#include "elf/elf_api_interface.h"
+
+#include <furi.h>
+#include <storage/storage.h>
+
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+    FlipperApplicationPreloadStatusSuccess = 0,
+    FlipperApplicationPreloadStatusUnspecifiedError,
+    FlipperApplicationPreloadStatusInvalidFile,
+    FlipperApplicationPreloadStatusInvalidManifest,
+    FlipperApplicationPreloadStatusApiMismatch,
+    FlipperApplicationPreloadStatusTargetMismatch,
+} FlipperApplicationPreloadStatus;
+
+typedef enum {
+    FlipperApplicationLoadStatusSuccess = 0,
+    FlipperApplicationLoadStatusUnspecifiedError,
+    FlipperApplicationLoadStatusNoFreeMemory,
+    FlipperApplicationLoadStatusMissingImports,
+} FlipperApplicationLoadStatus;
+
+/**
+ * @brief Get text description of preload status
+ * @param status Status code
+ * @return String pointer to description
+ */
+const char* flipper_application_preload_status_to_string(FlipperApplicationPreloadStatus status);
+
+/**
+ * @brief Get text description of load status
+ * @param status Status code
+ * @return String pointer to description
+ */
+const char* flipper_application_load_status_to_string(FlipperApplicationLoadStatus status);
+
+typedef struct FlipperApplication FlipperApplication;
+
+typedef struct {
+    const char* name;
+    uint32_t address;
+} FlipperApplicationMemoryMapEntry;
+
+typedef struct {
+    uint32_t mmap_entry_count;
+    FlipperApplicationMemoryMapEntry* mmap_entries;
+    uint32_t debug_link_size;
+    uint8_t* debug_link;
+} FlipperApplicationState;
+
+/**
+ * @brief Initialize FlipperApplication object
+ * @param storage Storage instance
+ * @param api_interface ELF API interface to use for pre-loading and symbol resolving
+ * @return Application instance
+ */
+FlipperApplication*
+    flipper_application_alloc(Storage* storage, const ElfApiInterface* api_interface);
+
+/**
+ * @brief Destroy FlipperApplication object
+ * @param app Application pointer
+ */
+void flipper_application_free(FlipperApplication* app);
+
+/**
+ * @brief Validate elf file and load application metadata 
+ * @param app Application pointer
+ * @return Preload result code
+ */
+FlipperApplicationPreloadStatus
+    flipper_application_preload(FlipperApplication* app, const char* path);
+
+/**
+ * @brief Get pointer to application manifest for preloaded application
+ * @param app Application pointer
+ * @return Pointer to application manifest
+ */
+const FlipperApplicationManifest* flipper_application_get_manifest(FlipperApplication* app);
+
+/**
+ * @brief Load sections and process relocations for already pre-loaded application
+ * @param app Application pointer
+ * @return Load result code
+ */
+FlipperApplicationLoadStatus flipper_application_map_to_memory(FlipperApplication* app);
+
+/**
+ * @brief Get state object for loaded application 
+ * @param app Application pointer
+ * @return Pointer to state object
+ */
+const FlipperApplicationState* flipper_application_get_state(FlipperApplication* app);
+
+/**
+ * @brief Create application thread at entry point address, using app name and
+ * stack size from metadata. Returned thread isn't started yet. 
+ * Can be only called once for application instance.
+ * @param app Applicaiton pointer
+ * @param args Object to pass to app's entry point
+ * @return Created thread
+ */
+FuriThread* flipper_application_spawn(FlipperApplication* app, void* args);
+
+/**
+ * @brief Get previously spawned thread
+ * @param app Application pointer
+ * @return Created thread
+ */
+FuriThread* flipper_application_get_thread(FlipperApplication* app);
+
+/**
+ * @brief Return relocated and valid address of app's entry point
+ * @param app Application pointer
+ * @return Address of app's entry point
+ */
+void const* flipper_application_get_entry_address(FlipperApplication* app);
+
+#ifdef __cplusplus
+}
+#endif