flint: Improve the logging widget

This PR improve stuffs around the logging widget.

Closes #3466 (closed)

For users:

• Update the color scheme
• Allow to edit logger levels with widget
• Lower overhead when the logging window is displayed
• No overhead when the logging window is closed

Internally:

• Added tolbar to edit python logging levels
• Added profiles to switch to predefined logging levels
• Create a Qt model to fully decouple the widget and the logging
• No more sync calls between logging handler and the widget
• The widget display log record by bunch (to reduce the use of slow commands)