[kcms/activities] Fixup DBus path usage
In a code cleanup the path name got corrupted. The use of macros obfuscates what can be done with a simple string. This code takes it back to what's helpful.
Whilst we're at it, ResourceScoring was using QDBusInterface and string based method names. This means synchronous calls, and also can get easily broken in future porting, so this is switched to using the generated interface.
Edited by David Edmundson