Adds a "Show session" button to notifications, which, when clicked, will focus the originating session.
Original patch by Kasper Laudrup at bug 305162, then updated by Martin T. H. Sandsmark.
Now updated and extended to silence/activity/process termination notifications, adding support for focusing a TerminalDisplay inside a hierarchy of ViewSplitters inside a TabbedViewContainer, and using KWindowSystem::forceActiveWindow() instead of ::activateWindow().