Refactor app launching (#174)

- Refactor the way apps work: Instead of a C interface, they are now C++ classes. The main reasoning is that attaching data to an app was cumbersome. Having different implementations for different kinds of apps was cumbersome too. (3 or 4 layers of manifest nesting for the TactilityC project)
- External apps are still written in C, but they get a createData/destroyData in their manifest, so:
- External apps now have their own manifest.
- All functions in the original AppManifest are removed and replaced by a single `createApp` function
- External apps now automatically register (each app individually!) when they run the first time. As a side-effect they become visible in the `AppList` app!
- Adapted all apps for the new interface.
- Adapted all internal logic for these changes (Gui, ViewPort, Loader, AppContext, AppInstance, etc.)
- Rewrote parts of Loader to use std::shared_ptr to make the code much safer.
- Added a refcount check for the `AppInstance` and `App` at the end of their lifecycle. Show warning if refcount is too high.

Tactility/Private/app/files/FilesPrivate.h

@@ -1,34 +0,0 @@
-#pragma once
-
-#include "./View.h"
-#include "./State.h"
-
-#include "app/AppManifest.h"
-
-#include <lvgl.h>
-#include <dirent.h>
-#include <memory>
-
-namespace tt::app::files {
-
-class Files {
-    std::unique_ptr<View> view;
-    std::shared_ptr<State> state;
-
-public:
-    Files() {
-        state = std::make_shared<State>();
-        view = std::make_unique<View>(state);
-    }
-
-    void onShow(lv_obj_t* parent) {
-        view->init(parent);
-    }
-
-    void onResult(Result result, const Bundle& bundle) {
-        view->onResult(result, bundle);
-    }
-};
-
-
-} // namespace

Tactility/Private/app/files/View.h

@@ -35,7 +35,7 @@ public:
     void onRenamePressed();
     void onDeletePressed();
     void onDirEntryListScrollBegin();
-    void onResult(Result result, const Bundle& bundle);
+    void onResult(Result result, std::unique_ptr<Bundle> bundle);
 };
 
 }