ui: Indexing UI

* Added DialogView with QtDialogView implementation to handle information dialogs
* Implemented QtIndexingDialog class that covers all different dialogs for indexing
* Directly communicate with DialogView from Prpject and all Tasks involved in indexing
* Block QtMainWindow UI while indexing

src/lib/data/PersistentStorage.cpp

@@ -366,6 +366,8 @@ void PersistentStorage::logStats() const
 
 void PersistentStorage::startParsing()
 {
+	clearCaches();
+
 	MessageClearErrorCount().dispatch();
 
 	m_sqliteStorage.setVersion();