[FL-3097] fbt, faploader: minimal app module implementation (#2420)

* fbt, faploader: minimal app module implementation
* faploader, libs: moved API hashtable core to flipper_application
* example: compound api
* lib: flipper_application: naming fixes, doxygen comments
* fbt: changed `requires` manifest field behavior for app extensions
* examples: refactored plugin apps; faploader: changed new API naming; fbt: changed PLUGIN app type meaning
* loader: dropped support for debug apps & plugin menus
* moved applications/plugins -> applications/external
* Restored x bit on chiplist_convert.py
* git: fixed free-dap submodule path
* pvs: updated submodule paths
* examples: example_advanced_plugins.c: removed potential memory leak on errors
* examples: example_plugins: refined requires
* fbt: not deploying app modules for debug/sample apps; extra validation for .PLUGIN-type apps
* apps: removed cdefines for external apps
* fbt: moved ext app path definition
* fbt: reworked fap_dist handling; f18: synced api_symbols.csv
* fbt: removed resources_paths for extapps
* scripts: reworked storage
* scripts: reworked runfap.py & selfupdate.py to use new api
* wip: fal runner
* fbt: moved file packaging into separate module
* scripts: storage: fixes
* scripts: storage: minor fixes for new api
* fbt: changed internal artifact storage details for external apps
* scripts: storage: additional fixes and better error reporting; examples: using APP_DATA_PATH()
* fbt, scripts: reworked launch_app to deploy plugins; moved old runfap.py to distfap.py
* fbt: extra check for plugins descriptors
* fbt: additional checks in emitter
* fbt: better info message on SDK rebuild
* scripts: removed requirements.txt
* loader: removed remnants of plugins & debug menus
* post-review fixes

lib/flipper_application/plugins/plugin_manager.h

@@ -0,0 +1,82 @@
+#pragma once
+
+#include <flipper_application/flipper_application.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Object that manages plugins for an application
+ * Implements mass loading of plugins and provides access to their descriptors
+ */
+typedef struct PluginManager PluginManager;
+
+typedef enum {
+    PluginManagerErrorNone = 0,
+    PluginManagerErrorLoaderError,
+    PluginManagerErrorApplicationIdMismatch,
+    PluginManagerErrorAPIVersionMismatch,
+} PluginManagerError;
+
+/**
+ * @brief Allocates new PluginManager
+ * @param application_id Application ID filter - only plugins with matching ID will be loaded
+ * @param api_version Application API version filter - only plugins with matching API version
+ * @param api_interface Application API interface - used to resolve plugins' API imports
+ *  If plugin uses private application's API, use CompoundApiInterface
+ * @return new PluginManager instance
+ */
+PluginManager* plugin_manager_alloc(
+    const char* application_id,
+    uint32_t api_version,
+    const ElfApiInterface* api_interface);
+
+/**
+ * @brief Frees PluginManager
+ * @param manager PluginManager instance
+ */
+void plugin_manager_free(PluginManager* manager);
+
+/**
+ * @brief Loads single plugin by full path
+ * @param manager PluginManager instance
+ * @param path Path to plugin
+ * @return Error code
+ */
+PluginManagerError plugin_manager_load_single(PluginManager* manager, const char* path);
+
+/**
+ * @brief Loads all plugins from specified directory
+ * @param manager PluginManager instance
+ * @param path Path to directory
+ * @return Error code
+ */
+PluginManagerError plugin_manager_load_all(PluginManager* manager, const char* path);
+
+/**
+ * @brief Returns number of loaded plugins
+ * @param manager PluginManager instance
+ * @return Number of loaded plugins
+ */
+uint32_t plugin_manager_get_count(PluginManager* manager);
+
+/**
+ * @brief Returns plugin descriptor by index
+ * @param manager PluginManager instance
+ * @param index Plugin index
+ * @return Plugin descriptor
+ */
+const FlipperAppPluginDescriptor* plugin_manager_get(PluginManager* manager, uint32_t index);
+
+/**
+ * @brief Returns plugin entry point by index
+ * @param manager PluginManager instance
+ * @param index Plugin index
+ * @return Plugin entry point
+ */
+const void* plugin_manager_get_ep(PluginManager* manager, uint32_t index);
+
+#ifdef __cplusplus
+}
+#endif