Enhance the UI framework of OpenOlat to allow opening several windows:
- Server side distinguish between a) reload, b) back, c) open in new window and d) copy paste in new window
- For case c and d create a window on the server and dispatch the call in this window
- Deal with all the special cases that arise from these changes
- Optimize detection of closed windows for larger disposal and memory optimization
The goal of this issue is to implement the base infrastructure. In subsequent releases the feature will be made available once all in-app issues have been detected and solved.