[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.c

@@ -0,0 +1,131 @@
+#include "flipper_application.h"
+#include "flipper_application_i.h"
+
+#define TAG "fapp"
+
+/* For debugger access to app state */
+FlipperApplication* last_loaded_app = NULL;
+
+FlipperApplication*
+    flipper_application_alloc(Storage* storage, const ElfApiInterface* api_interface) {
+    FlipperApplication* app = malloc(sizeof(FlipperApplication));
+    app->api_interface = api_interface;
+    app->fd = storage_file_alloc(storage);
+    app->thread = NULL;
+    return app;
+}
+
+void flipper_application_free(FlipperApplication* app) {
+    furi_assert(app);
+
+    if(app->thread) {
+        furi_thread_join(app->thread);
+        furi_thread_free(app->thread);
+    }
+
+    last_loaded_app = NULL;
+
+    if(app->state.debug_link_size) {
+        free(app->state.debug_link);
+    }
+
+    if(app->state.mmap_entries) {
+        free(app->state.mmap_entries);
+    }
+
+    ELFSection_t* sections[] = {&app->text, &app->rodata, &app->data, &app->bss};
+    for(size_t i = 0; i < COUNT_OF(sections); i++) {
+        flipper_application_free_section(sections[i]);
+    }
+
+    storage_file_free(app->fd);
+
+    free(app);
+}
+
+/* Parse headers, load manifest */
+FlipperApplicationPreloadStatus
+    flipper_application_preload(FlipperApplication* app, const char* path) {
+    if(!flipper_application_load_elf_headers(app, path) ||
+       !flipper_application_load_section_table(app)) {
+        return FlipperApplicationPreloadStatusInvalidFile;
+    }
+
+    if((app->manifest.base.manifest_magic != FAP_MANIFEST_MAGIC) &&
+       (app->manifest.base.manifest_version == FAP_MANIFEST_SUPPORTED_VERSION)) {
+        return FlipperApplicationPreloadStatusInvalidManifest;
+    }
+
+    if(app->manifest.base.api_version.major != app->api_interface->api_version_major /* ||
+       app->manifest.base.api_version.minor > app->api_interface->api_version_minor */) {
+        return FlipperApplicationPreloadStatusApiMismatch;
+    }
+
+    return FlipperApplicationPreloadStatusSuccess;
+}
+
+const FlipperApplicationManifest* flipper_application_get_manifest(FlipperApplication* app) {
+    return &app->manifest;
+}
+
+FlipperApplicationLoadStatus flipper_application_map_to_memory(FlipperApplication* app) {
+    last_loaded_app = app;
+    return flipper_application_load_sections(app);
+}
+
+const FlipperApplicationState* flipper_application_get_state(FlipperApplication* app) {
+    return &app->state;
+}
+
+FuriThread* flipper_application_spawn(FlipperApplication* app, void* args) {
+    furi_check(app->thread == NULL);
+
+    const FlipperApplicationManifest* manifest = flipper_application_get_manifest(app);
+    furi_check(manifest->stack_size > 0);
+
+    app->thread = furi_thread_alloc();
+    furi_thread_set_stack_size(app->thread, manifest->stack_size);
+    furi_thread_set_name(app->thread, manifest->name);
+    furi_thread_set_callback(app->thread, (entry_t*)app->entry);
+    furi_thread_set_context(app->thread, args);
+
+    return app->thread;
+}
+
+FuriThread* flipper_application_get_thread(FlipperApplication* app) {
+    return app->thread;
+}
+
+void const* flipper_application_get_entry_address(FlipperApplication* app) {
+    return (void*)app->entry;
+}
+
+static const char* preload_status_strings[] = {
+    [FlipperApplicationPreloadStatusSuccess] = "Success",
+    [FlipperApplicationPreloadStatusUnspecifiedError] = "Unknown error",
+    [FlipperApplicationPreloadStatusInvalidFile] = "Invalid file",
+    [FlipperApplicationPreloadStatusInvalidManifest] = "Invalid file manifest",
+    [FlipperApplicationPreloadStatusApiMismatch] = "API version mismatch",
+    [FlipperApplicationPreloadStatusTargetMismatch] = "Hardware target mismatch",
+};
+
+static const char* load_status_strings[] = {
+    [FlipperApplicationLoadStatusSuccess] = "Success",
+    [FlipperApplicationLoadStatusUnspecifiedError] = "Unknown error",
+    [FlipperApplicationLoadStatusNoFreeMemory] = "Out of memory",
+    [FlipperApplicationLoadStatusMissingImports] = "Found unsatisfied imports",
+};
+
+const char* flipper_application_preload_status_to_string(FlipperApplicationPreloadStatus status) {
+    if(status >= COUNT_OF(preload_status_strings) || preload_status_strings[status] == NULL) {
+        return "Unknown error";
+    }
+    return preload_status_strings[status];
+}
+
+const char* flipper_application_load_status_to_string(FlipperApplicationLoadStatus status) {
+    if(status >= COUNT_OF(load_status_strings) || load_status_strings[status] == NULL) {
+        return "Unknown error";
+    }
+    return load_status_strings[status];
+}