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.

{F7497259}

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