Add support for KUserFeedback
This commit introduces KUserFeedback in dolphin with some basic data sources and with a settings page to configure the telemetry values.
The settings page is shown only if the user feedback framework is enabled, but currently in Plasma we don't have a global kill switch to disable it AFAICS.
At the moment we never show an encouragement message. We need to connect
to the Provider::showEncouragementMessage() signal, but first we
should agree to a common way to show a non-annoying message to the users.
There are also a couple custom data sources as proof of concept: a bunch of settings and the count of available network shares as listed by Solid.:
Edited by Elvis Angelaccio