Improve layout handling
- Handle layouts on multiple screens better
- Dock widget positions better
- Allow to save layouts per projects etc.
- Detach timeline dock
- Evaluate if switching to [KDDockWidgets](https://www.kdab.com/software-technologies/developer-tools/kddockwidgets/) makes sense
- #1534
- #1292
- #1790
- #1999
- #1360
issue