Add find remote device plugin
Summary: Counterpart for D11773
Test Plan: Apply D11773, hit Ring, hear sound. Phone to phone works too
Reviewers: KDE Connect, albertvaka
Reviewed By: KDE Connect, albertvaka
Subscribers: albertvaka, kdeconnect, kossebau, KDE Connect
Tags: KDE Connect
Differential Revision: https://phabricator.kde.org/D12344