community/plasma-desktop-meta: depend on power-profiles-daemon

It's an optional but recommended dependency of powerdevil with which it allows the user to switch between 3 power profiles (conservative, balanced, performance) which impacts performance and battery life. Since powerdevil functions perfectly fine without it I'm putting the dependency here so people can choose to not install it if they so desire.

@gnumdk this moves testing/power-profiles-daemon to community, are you ok with this? It seems you haven't touched this package since you submitted it, do you still want to maintain it or should I take over?