accept discord token as env

we only really need that to function anyway, other things like jellyfin will
just not do anything and we have default value for avatar reset.

lib/avatarRotation.js

@@ -1,6 +1,9 @@
+let config = {};
+try { config = require('./config.json'); }
+catch { config.token = process.env.DISCORD; }
+
 const fs = require('fs');
 const path = require('path');
-const config = require('../config.json');
 
 const AVATAR_DIR = path.join(__dirname, '../avatars');
 let avatarFiles = [];