Add support for an idle time interface
The idle time interface is modelled for the use cases of the KIdleTime framework to allow providing a Wayland specific implementation. It supports registering idle timeouts which are triggered on server side if there has not been any user activity on the seat for the requested amount of time. Once user activity resumes a resume from idle signal is emitted. In additon there is the possibility to simulate user activity which simulates the resume from idle.