2282285  bulk docs endpoint

Implementation of bulk docs endpoint.
All entities needs to be nested under a "docs" key, like in the API specification:
`"docs": [
    {
      "_id": "FishStew"
    },
    {
      "_id": "LambStew",
      "_rev": "2-0786321986194c92dd3b57dfbfc741ce",
      "_deleted": true
    }
  ]
}`