Example response models

This is used in the application API documentation already, but having example JSON models for the applicable endpoints that can be used as references for people using the API, similarly to the [Dashflo API docs](https://dashflo.net/docs/api/pterodactyl/v1/).

Start by reviewing the existing application API documentation and the comparable Dashflo API docs linked in the issue. Identify the applicable endpoints and add example JSON response models as references; it is done when each relevant endpoint has a documented example.

索引モデルが issue の本文から書いたものです。