Implemented LaunchId and FileSelection, updated Notes (#281)

- Implemented `LaunchId` to keep track of the apps that are started
- Implemented `FileSelection` app to select existing and/or new files.
- Moved some re-usable file functionality to `tt::file::`
- Renamed `Files` app to `FileBrowser`
- Updated `Notes` app to use new `FileSelection` functionality, and cleaned it up a bit.
- General code cleanliness improvements

Tactility/Source/app/filebrowser/FileBrowser.cpp

@@ -0,0 +1,47 @@
+#include "Tactility/app/filebrowser/View.h"
+#include "Tactility/app/filebrowser/State.h"
+#include "Tactility/app/AppContext.h"
+
+#include <Tactility/Assets.h>
+#include <Tactility/service/loader/Loader.h>
+
+#include <memory>
+
+namespace tt::app::filebrowser {
+
+#define TAG "filebrowser_app"
+
+extern const AppManifest manifest;
+
+class FileBrowser : public App {
+    std::unique_ptr<View> view;
+    std::shared_ptr<State> state;
+
+public:
+    FileBrowser() {
+        state = std::make_shared<State>();
+        view = std::make_unique<View>(state);
+    }
+
+    void onShow(AppContext& appContext, lv_obj_t* parent) override {
+        view->init(parent);
+    }
+
+    void onResult(AppContext& appContext, TT_UNUSED LaunchId launchId, Result result, std::unique_ptr<Bundle> bundle) override {
+        view->onResult(result, std::move(bundle));
+    }
+};
+
+extern const AppManifest manifest = {
+    .id = "Files",
+    .name = "Files",
+    .icon = TT_ASSETS_APP_ICON_FILES,
+    .type = Type::Hidden,
+    .createApp = create<FileBrowser>
+};
+
+void start() {
+    service::loader::startApp(manifest.id);
+}
+
+} // namespace