:necktie: Update middleware-execution logic
:necktie: Update middleware-execution logic

- The check if the middleware exists will now be done before calling it and after calling the `before` middleware if there is any
- `before` and `after` middlewares will now be called no matter if the middleware without prefix exists
- Implemented `clear` method for `MiddlewareCollection`

jovotech/jovo-framework-nodejs,jovotech/jovo-framework-nodejs