Add System Audio Support

[darshkpatel]

Taking input directly from the system audio instead of Microphone seems integral

This issue will be used to track the progress of the feature

[darshkpatel]

Update: Currently busy with academics, will resume work on this after University exams are over

[AstroOrbis]

Good luck :)

[jmac9595]

Having found a previous touch bar visualizer that worked but was kinda ugly, I was super happy to stumble across this one! Thank you man. For those looking for computer audio, I used Blackhole 2ch (https://github.com/ExistentialAudio/BlackHole/wiki) and Audio MIDI setup app that comes with macOS to make it work.

1. Download and install blackhole 2ch
2. in Audio Midi setup app, set up a multiple-output device that routes audio to your speakers/headphones and Blackhole 2ch -- check both boxes. [I'll see if my screenshot works]

3. Go to sound settings in the system settings/preferences app and select the aggregate device (usually named Multi-Output device) as your sound output and Blackhole 2ch as your input mic. Then you can get system sound routed to both the Touch Bar and your speakers.
   Hope this helps! Thank you again @darshkpatel for your work.