API breaking change in main

61f7650e changed the name of the Driver dictionary member to CpuDriver and PlatformDriver.

This dictionary member should stay, maybe with a dummy value, so as not to break API. The Driver member is used in powerprofilesctl (an older version of the tool should run against the new daemon), and gnome-control-center for debugging.

src/net.hadess.PowerProfiles.xml should also be updated to mention the new dictionary keys used.

CC: @superm1