Add methods to MetadataManager for the e-logbook

We need a method to send information to the e-logbook. Structure to be sent is:

{
  "investigationId": 0,
  "datasetId": 0,
  "type": "notification",
  "content": [
    {
      "format": "string",
      "text": "string"
    }
  ],
  "tags": [
    "string"
  ],
  "title": "string",
  "category": "commandline",
  "filepath": "string",
  "filename": "string",
  "fileSize": "string",
  "username": "string",
  "software": "string",
  "machine": "string",
  "creationDate": "Unknown Type: date",
  "contentType": "string",
  "file": "string"
}

By using the following URL: [POST] /investigations/{investigationId}/events

It should also have a valid account where it could log events. This specific account can not be ingester and only could create events in the elogbook. Nothing else.