Invite a user to a project

{
  "invitations": [
    {
      "invitation": {
        "meta": {
          "title": "Some title",
          "category": "metadataType",
          "tags": "tag1 tag2",
          "author": "/gdc/account/profile/p123",
          "created": "2020-01-08 15:44:23",
          "contributor": "/gdc/account/profile/p123",
          "updated": "2020-01-08 15:44:23",
          "identifier": "identifier123",
          "summary": "Object summary",
          "uri": "/gdc/uri/self"
        },
        "content": {
          "userFilters": [
            "/gdc/md/{project_id}/obj/{object_id}"
          ],
          "role": "/gdc/projects/{project_id}/roles/{role_id}"
        },
        "links": {
          "self": "/gdc/projects/{project}/invitations/{invitation}",
          "project": "/gdc/projects/{project}",
          "profile": "/gdc/account/profile/{user_id}"
        }
      }
    }
  ]
}

{
  "createdInvitations": {
    "uri": [
      "/gdc/projects/{project_id}/invitations/{invitation_id}"
    ]
  }
}