KCM Notification port to ManagedConfigModule

Summary: Require D26047 At least, the properties of Notification tab in the KCM is handled properly.

Reviewers: #plasma, ervin, bport, mart, davidedmundson, meven

Reviewed By: #plasma, davidedmundson

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D26048