Remove old unused service worker file

public/custom-service-worker.js

@@ -1,19 +0,0 @@
-// List of extra files to be precached for offline use.
-// WARNING: don't forget to update the revision string after updating these files.
-self.__precacheManifest = (self.__precacheManifest || []).concat([
-    {
-        "revision": "1",
-        "url": "/webminidisc/atracdenc.js"
-    },
-    {
-        "revision": "1",
-        "url": "/webminidisc/worker.min.js"
-    },
-    {
-        "revision": "1",
-        "url": "/webminidisc/ffmpeg-core.js"
-    },
-]);
-importScripts(
-    "/webminidisc/service-worker.js"
-);