Summary: This plugin allows controlling the system value from a remote device.

Test Plan: Apply Android patch, open up MPRIS Activity and play with the slider

Reviewers: #kde_connect, mtijink, albertvaka

Reviewed By: #kde_connect, albertvaka

Subscribers: kdeconnect, apol, zhigalin, albertvaka, davidedmundson, mtijink, #kde_connect

Tags: #kde_connect

Maniphest Tasks: T4659

Differential Revision: https://phabricator.kde.org/D7992