Added: Enhanced spdier log/error handling

[starrify]

Collects not only spider exceptions, but also other kinds of errors that appear in logs. E.g.:

{
  "status": "ok",
  "errors": [
    "Ignoring response <404 https://www.linkedin.com/in/no_such_profile>: HTTP status code is not handled or not allowed"
  ],
  "items": []
}

Currently for reviewing purpose only. Please do not merge until there're unit tests added.