- This is the first version with still a lot of broken and missing features. There's a new ToolboxUIBase
class, which contains a QStackedWidget with two QMainWindow pages. The Main window is now
either in 'expert mode', which is the old ToolboxUI main window, or  in 'user mode', which is a brand
new ToolboxUILite main window.

- Fixed the resizing problem in Properties dock widget

Re #2794

# Conflicts resolved in:
#	spinetoolbox/main.py
#	spinetoolbox/ui_main.py
#	tests/mock_helpers.py

- Call SetPos after a Group moves when an item in the Group is moved
- Fix Renaming Groups
- Fix Ungrouping

# Fixed conflicts in:
#	spinetoolbox/resources_icons_rc.py
#	spinetoolbox/ui/mainwindow.py
#	spinetoolbox/ui/mainwindow.ui
#	spinetoolbox/ui_main.py
#	spinetoolbox/widgets/custom_qtextbrowser.py
#	tests/mock_helpers.py
#	tests/test_SpineToolboxProject.py
#	tests/test_ToolboxUI.py

# Fixed conflicts in:
#	spinetoolbox/resources_icons_rc.py
#	spinetoolbox/ui/mainwindow.py
#	spinetoolbox/ui/mainwindow.ui