[web-src] Add option to stream audio from player web interface

The audio implementation is based on
https://github.com/rainner/soma-fm-player and makes use of the  HTML5
Web Audio Context API.

web-src/vue.config.js

@@ -24,10 +24,13 @@ module.exports = {
     // localhost:3689
     proxy: {
       '/api': {
-        target: 'http://localhost:3689',
+        target: 'http://localhost:3689'
       },
       '/artwork': {
-        target: 'http://localhost:3689',
+        target: 'http://localhost:3689'
+      },
+      '/stream.mp3': {
+        target: 'http://localhost:3689'
       }
     }
   }