List app features endpoint should not (pretend to) support pagination

Issue

The GET /v3/apps/:guid/features endpoint "pretends" to support pagination - it returns a pagination object. But neither per_page nor order_by are working. Also the first and last links are incorrect.

Context

No response

Steps to Reproduce

No response

Expected Result

With pagination removed:

{
  "resources": [
    {
      "name": "ssh",
      "description": "Enable SSHing into the app.",
      "enabled": true
    },
    {
      "name": "revisions",
      "description": "Enable versioning of an application",
      "enabled": true
    },
    {
      "name": "service-binding-k8s",
      "description": "Enable k8s service bindings for the app",
      "enabled": true
    },
    {
      "name": "file-based-vcap-services",
      "description": "Enable file-based VCAP service bindings for the app",
      "enabled": false
    }
  ]
}

With pagination removed and links added:

{
  "resources": [
    {
      "name": "ssh",
      "description": "Enable SSHing into the app.",
      "enabled": true
    },
    {
      "name": "revisions",
      "description": "Enable versioning of an application",
      "enabled": true
    },
    {
      "name": "service-binding-k8s",
      "description": "Enable k8s service bindings for the app",
      "enabled": true
    },
    {
      "name": "file-based-vcap-services",
      "description": "Enable file-based VCAP service bindings for the app",
      "enabled": false
    }
  ],
  "links": {
    "self": {
      "href": "https://api.example.org/v3/apps/b832f30f-bd3c-47a4-9192-1194835ef854/features"
    },
    "app": {
      "href": "https://api.example.org/v3/apps/b832f30f-bd3c-47a4-9192-1194835ef854"
    }
  }
}

Current Result

{
  "resources": [
    {
      "name": "ssh",
      "description": "Enable SSHing into the app.",
      "enabled": true
    },
    {
      "name": "revisions",
      "description": "Enable versioning of an application",
      "enabled": true
    },
    {
      "name": "service-binding-k8s",
      "description": "Enable k8s service bindings for the app",
      "enabled": true
    },
    {
      "name": "file-based-vcap-services",
      "description": "Enable file-based VCAP service bindings for the app",
      "enabled": false
    }
  ],
  "pagination": {
    "total_results": 4,
    "total_pages": 1,
    "first": {
      "href": "/v3/apps/b832f30f-bd3c-47a4-9192-1194835ef854/features"
    },
    "last": {
      "href": "/v3/apps/b832f30f-bd3c-47a4-9192-1194835ef854/features"
    },
    "next": null,
    "previous": null
  }
}

Possible Fix

I'm proposing to remove pagination from the response and maybe(?) add links instead (like it's done for GET /v3/apps/:guid/environment_variables).

Start by tracing the GET /v3/apps/:guid/features endpoint and locate its response and endpoint tests. Compare the current response with the examples in this issue, then verify that the finished behavior has no pagination object and has the expected app and self links if links are included.