Provide a telemetrics kcm module for Plasma

Summary:
It offers 2 main features:

• Configure the system-wide KUserFeedback kill-switch
• Provide a setting for how much information we want our Plasma to be sending

Test Plan:
Tested it together with Discover, works fine.

Reviewers: Plasma, vkrause, ngraham

Reviewed By: ngraham

Subscribers: aspotashev, ngraham, bcooksley, davidedmundson, ognarb, broulik, plasma-devel

Tags: Plasma

Differential Revision: https://phabricator.kde.org/D24011