globalaccel: allow sleep and hibernate keyboard shortcuts
Summary:
This is useful for the phone specially. You can quickly turn on-off your
phone from lockscreen without actually unlocking it.
Test Plan: I need help testing it as my prefix session is broken currently.
Reviewers: Plasma, davidedmundson
Reviewed By: Plasma, davidedmundson
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D27721