[mpriscontrol] add primitive windows support

Summary: Added primitive support for the mpriscontrol plugin on Windows by simulating VK_MEDIA key presses. I took a look into ISystemMediaTransportControls, but there doesn't seem to query it since it's per app. Leaving simulating key presses our only option for now. Completes T10000

Reviewers: kdeconnect, KDE Connect, albertvaka

Reviewed By: KDE Connect, albertvaka

Subscribers: albertvaka

Tags: KDE Connect, Windows

Maniphest Tasks: T10000

Differential Revision: https://phabricator.kde.org/D17702