Add Dbus support

[cypherpower]

Very initial work done here, using the existing DBUS interface used by KDE and GNOME following org.freedesktop.UPower.PowerProfiles this is meant to be a drop-in replacement for power-profiles-daemon. I have done some initial testing with the KDE systemsettings application and it is working there for the few settings I tested. Will need to do significantly more testing, especially with the Gnome settings.

[AdnanHodzic]

What exactly would be the benefit of adding Dbus support? To make it with the power sliders (and other elements, e.g: system tray) in GNOME, KDE, etc and have auto-cpufreq serve as backend provider?

Please note that auto-cpufreq will disable power-profiles-daemon when daemon is installed as also indicated in Readme. Of course, it'll restore it in case auto-cpufreq is removed.

Since GNOME Power Profiles service was developed much later after auto-cpufreq and such is deemed redundant, as if it runs in parallel with auto-cpufreq it'll cause issues and they'll keep conflicting with each other in decision making process.

[cypherpower]

What exactly would be the benefit of adding Dbus support? To make it with the power sliders (and other elements, e.g: system tray) in GNOME, KDE, etc and have auto-cpufreq serve as backend provider?

Benefit would be just as you said, a backend service for the GUI tools like Gnome Settings and KDE System settings, making a Desktop Environment's native features be able to utilize auto-cpufreq as a drop-in replacement for the power-profiles-daemon.