Update error handling

[mrexmelle]

Description

Currently there's no singular way to return response. This ticket requires HTTP responses to return with the following format for responses with data:

{
 "data": $(data)
 "error": {
    "code": $(app_specific_error_code)
    "message": $(error_from_error_obj)
  }
}

And for responses without data:

{
 "error": {
    "code": $(app_specific_error_code)
    "message": $(error_from_error_obj)
  }
}