feat(App): add an import qml path for plugins

src/app/App.cpp

@@ -142,6 +142,7 @@ inline void activeSplashScreen (QQmlApplicationEngine *engine) {
 
 void App::initContentApp () {
   shared_ptr<linphone::Config> config = ::getConfigIfExists(*mParser);
+  const QString pluginsPath = ::Utils::coreStringToAppString(Paths::getPluginsDirPath());
 
   // Destroy qml components and linphone core if necessary.
   if (mEngine) {
@@ -167,7 +168,7 @@ void App::initContentApp () {
       });
 
     // Add plugins directory.
-    addLibraryPath(::Utils::coreStringToAppString(Paths::getPluginsDirPath()));
+    addLibraryPath(pluginsPath);
     qInfo() << QStringLiteral("Library paths:") << libraryPaths();
   }
 
@@ -185,6 +186,8 @@ void App::initContentApp () {
   mEngine->addImportPath(":/ui/modules");
   mEngine->addImportPath(":/ui/scripts");
   mEngine->addImportPath(":/ui/views");
+  mEngine->addImportPath(pluginsPath);
+  qInfo() << QStringLiteral("Engine import paths:") << mEngine->importPathList();
 
   // Provide avatars/thumbnails providers.
   mEngine->addImageProvider(AvatarProvider::PROVIDER_ID, new AvatarProvider());