Add helper function to clean up directory entries

nuxeo.directory('nature')
  .fetchAll()
  .then(function(data) {
    console.log(JSON.stringify(data.entries, null, 2))
  })

{
  "_baseOptions": {
    "schemas": [],
    "enrichers": {},
    "fetchProperties": {},
    "translateProperties": {},
    "headers": {
      "Authorization": "Basic !!!REMOVED!!!",
      "Accept": "application/json"
    },
    "timeout": 30000,
    "httpTimeout": 30000
  },
  "_directory": {
    "_baseOptions": {
      "schemas": [],
      "enrichers": {},
      "fetchProperties": {},
      "translateProperties": {},
      "headers": {},
      "httpTimeout": 30000
    },
    "_nuxeo": {
      "_baseOptions": {
        "schemas": [],
        "enrichers": {},
        "fetchProperties": {},
        "translateProperties": {},
        "headers": {},
        "httpTimeout": 30000
      },
      "_baseURL": "http://localhost:8080/nuxeo/",
      "_restURL": "http://localhost:8080/nuxeo/api/v1/",
      "_automationURL": "http://localhost:8080/nuxeo/api/v1/automation/",
      "_auth": {
        "method": "basic",
        "username": "Administrator",
        "password": "Administrator"
      },
      "_authenticationRefreshedListeners": [],
      "connected": false,
      "_activeRequests": 0
    },
    "_directoryName": "nature",
    "_path": "directory/nature"
  },
  "properties": {
    "ordering": 10000000,
    "obsolete": 0,
    "id": "article",
    "label": "label.directories.nature.article"
  },
  "_dirtyProperties": {
    "ordering": 10000000,
    "obsolete": 0,
    "id": "article",
    "label": "label.directories.nature.article"
  },
  "entity-type": "directoryEntry",
  "directoryName": "nature",
  "id": "article"
}
.
.
.

// NUXEO DOC https://doc.nuxeo.com/rest-api/1/directory-entry-entity-type/
{
  "entity-type": "directoryEntry",
  "directoryName": string,
  "id": string,
  "properties": object,
  "contextParameters": object
}