bpo-30781: IDLE - Use ttk Notebook in ConfigDialog (#2938)

The notebook looks a bit better.  It will work better with separate page classes. Traversal of widgets by Tab works better.  Switching tabs with keys becomes possible.  The font sample box works better at large font sizes.

One of the two simulated click tests no longer works.  This will be investigated while fixing a bug with the widget itself.
3 files changed