refactor: new dev/prod containers

- Use a single Dockerfile for all Zeppelin services
- Add a Dockerfile in project root that can be used by
  app hosting services
- Provide a standalone and lightweight prod setup
  - Standalone is the same as the old setup, with mysql+nginx
  - Lightweight only runs bot+backend+dash, no mysql/nginx
- Remove mounted mysql data folders for dev and prod
  - This resolves permission issues caused by the mount
  - The mysql service uses a regular named volume now
- Simplify .env options and clearly separate different prod setups
- Remove update.sh
  - Different setups require different update procedures, so a common
    update.sh no longer works

backend/src/api/start.ts

@@ -51,7 +51,7 @@ app.use((req, res, next) => {
   return notFound(res);
 });
 
-const port = env.API_PORT;
+const port = 3001;
 app.listen(port, "0.0.0.0", () => console.log(`API server listening on port ${port}`)); // tslint:disable-line
 
 startBackgroundTasks();