Notifier consolidation

[vfjpl]

When I was looking at where notifier saves it's setting I wrote some consolidations code and was thinking about writing some module so there would be only one place with configuration. But then I had some different things to do. This patches consolidates code between notifier and notifier_kde.

[philmmanjaro]

@Kirek: code seems fine from my end. I found some time to review it. Maybe we need to apply it to see if there are any regressions ...

[Kirek]

Seems fine. thanks.