Add Web Service for testing of e-mail settings

Current Situation

• Users can configure a Job Resource to hold settings used to connect to a mail server.
• Settings are used
  • by JITL MailJob and MailInboxJob
  • by JS7 Notifications (Monitor Service)

Desired Behavior

• Users would like to test the mail server connectivity from the JOC Cockpit GUI.
• For a Job Resource of type "mail" the GUI offers
  • • input fields for the recipient and subject of a test mail
    • a button to send mail
• The Web Service will send mail synchronously from the settings of the current Job Resource. Any problems related to sending a test e-mail will be reported back to the user.

Implementation

• The REST Web Service is parameterized from
  • the name of the Job Resource
  • the recipient
  • the subject
• The Web Service will use the settings of the indicated Job Resource
  • The most recent version of the Job Resource will be used, independently from the fact that the Job Resource is deployed or is a draft.