elm - focus feature - add config option to automatically show/hide focus

elm - focus feature - add config option to automatically show/hide focus

this adds logic in elm widget and elm win to figure out how to
automatically show a focus hilight when switching focus, or to hide
it. this really should be the default mode, thus in all default
profiles (default, standard, mobile) it's turned on. this means if you
tab or shif+tab or use arrow keys to switch focus, the focus hilight
will magicallly appear. click with a mouse to change focus and it'll
disappear assuming you want to use the mouse to do things. If focus is
explicitly turned on in config or in the window by api, then this has
no effect and focus will remain on all the time. this adds apis to
change these config values and options in the default elm config tool
to swizzle them as well as config upgrade handling for existing configs.

@feature