text: Title: RFC: Temporary config value overrides
  Body: Often times you may need to change a config value for a particular duration, or perhaps for a single route handler. There should be a simple API to manage that.
  
  ```python
  with app.config.override(RESPONSE_TIMEOUT=99999):
      do_something()
  
  # or
  
  app.route("/", config_override={"RESPONSE_TIMEOUT":99999 })(...)
  ```
  
  A similar approach [can be found here](https://sanic-jwt.readthedocs.io/en/latest/pages/configuration.html#temporary-override).