Initial version of the adapt-authoring mailer module

Add this snippet (just as example!) to dev.config.js

...
,
   "adapt-authoring-mailer": {
    "isEnabled": true,
    "connectionUrl": "smtp://some@service.email:xyz@smtp.service.email"
},

On windows, if you get an error message like "error self signed certificate in certificate chain", it might be due your antivirus scanner: see nodemailer/nodemailer#406