Important notifications should be always shown.

[farmaazon]

Some notifications pushed to the notification list should be marked as important: those are immediately displayed, even if the list is hidden. User should be able to hide them. Some should define a time after which they will be hidden automatically.

Having such notification visible, when the list is shown, the already visible notifications should smoothly go to their place on the list. Then, if the user hides the list, no notifications should be visible until a new important notification arrives.

Acceptance Criteria

There should be a debug shortcut for pushing mocked important notification to the list

[farmaazon]

The tasks for #5201 should be redesigned for new GUI