Fix improve folder creation speed

[czullu]

To create a folder tree of around 500 Folders original code will take up to 8 minutes just for folder creation. A reason is, that multiple calls are repeated as Load for each folder like ContentTypes for Security Roles...

The new implementation checks with one query for FsObjectType=1 for existing Folders, builds the complete Folder tree and maps existing folders to it. Then it will handle the Folders by Tree Level. This way we reduce the calls and the overall processing time will be aprx 2min.