refactor: Rm body parser from proxy

The body parser was manipulating the request in transit which caused
POST reqests with json to hang and never reach the server

See this issue in http-proxy-middleware's github:
chimurai/http-proxy-middleware#40

app/proxy/src/classes/application.class.ts

@@ -12,7 +12,6 @@ export default class Application {
 
   constructor() {
     this.express = express();
-    this.express.use(express.json());
 
     this.logger = logger;
     this.environment = environment;