Add Mute button to PIP window

Love the app so far - best and simple out of all the iptv apps I've come across 👍 I love the PiP feature on macOS, but wish there was an option to mute the PiP window without having to exit out of PiP and mute from the main window. 

**Describe the solution you'd like**
Add a speaker icon to the the center of the window, adjacent to the pause button, to mute/unmute the audio. 

Thanks! 