EGLFS platform: Get inputs from sd-logind without root

Currently QT directly accesses input devices (such as /dev/input/event[0-9]*). This is only possible if the application is granted higher privileges or if the access modifiers of the input devices are relaxed, both workarounds have disadvantages.

The modern solution to this is to call TakeDevice() to get a fd from systemd-logind which does not require any increased privileges.