This caused a behavior change it wasn't clear how to use the
permission API to change the focus mode.
The change will only take effect if the user override the API
level.
This also pulls in part of the permission framework to ensure
backward compatibility is kept.
`awful.autofocus` was always weird. It is a module part of `awful`,
but it was never part of `awful` `init.lua`. Rather, `rc.lua` was
the sole place it was used. It behave exactly like a request, but
predate them by years. As I cleanup the request:: API before the
permissions API gets formalized, this has to be fixed now.
It isn't deprecated in this commit because it makes too many tests
fail. Another pull request will solve that by adding the "API level"
concept to AwesomeWM so I can change the behavior without breaking
existing configs. With that, the behavior of `autofocus` will be
enabled by default with the permissions to disable it.