GStreamer Spotify plugin

To play spotify songs you need a gstreamer spotify plugin from the gst-plugins-rs package usually not available on most systems. Also, currently it is necessary to use a modified version of the plugin.

git clone https://gitlab.freedesktop.org/kingosticks/gst-plugins-rs
cd gst-plugins-rs
git checkout spotify-uri-handler
cargo cbuild -p gst-plugin-spotify
sudo cp ./target/x86_64-unknown-linux-gnu/debug/libgstspotify.so /usr/lib64/gstreamer-1.0/