Send email when adding participant

- create invite email template
- move email config
- implement sendEmail functionality

helpers/logSmtpStatus.js

@@ -1,14 +0,0 @@
-const transporter = require('../services/email/transporter');
-
-function logSmtpStatus() {
-	transporter.verify(function (error, success) {
-		if (error) {
-			console.log('SMTP is not working, check your configuration.');
-			return ``;
-		} else {
-			console.log('SMTP is correctly configured.');
-		}
-	});
-}
-
-module.exports = logSmtpStatus;