Adds ability to navigate the applet using the keyboard.
Current actions implemented:
- Up/Down moves through the list
- Enter clicks the connect button
- Menu key acts as right-click
- Esc collapses the current item if expanded, else closes the applet
- Ctrl+F focuses the search field
Currently when you hit Enter to connect to a network and the mouse is somewhere in the list, the ListView reflows and focus lands on whatever item happened to be underneath. See frameworks/plasma-framework!345 (merged), but alternate solutions welcome. Done.