refactor(server): renamed ws server

Author: knagaitsev

lib/servers/WsServer.js renamed to lib/servers/WebsocketServer.js

@@ -5,4 +5,4 @@ const BaseServer = require('./BaseServer');
 
 // ws server implementation under construction
 // will need changes in the client as well to function
-module.exports = class WsServer extends BaseServer {};
+module.exports = class WebsocketServer extends BaseServer {};