Name: issue-service-definition
Type: request
Purpose: >
  Defines ("creates") a new issue service
Response: issue-service-details
Inherits: message
Elements:
  Signature: { required: true }
  From: { required: true }
  Issue-Service-Data: { required: true, type: object, class: issue_service }
Rejection-Codes:
  21: Missing attributes
  31: Sender is not authorized to define issue services
  41: Issue service is already defined for this event
  42: Could not fetch event data from voting server
  43: Event is not linked to this issue server
  44: ID provider or terms are undefined