KB68 Newsletter registration and deregistration.

Change-Id: Ic79fe64f03ce887879bffc7623e59cb697065ee6
diff --git a/src/main/resources/templates/NewsletterUnsubscriber/unsubscribedMail.txt b/src/main/resources/templates/NewsletterUnsubscriber/unsubscribedMail.txt
new file mode 100644
index 0000000..56f8d0e
--- /dev/null
+++ b/src/main/resources/templates/NewsletterUnsubscriber/unsubscribedMail.txt
@@ -0,0 +1,7 @@
+You have been unsubscribed from the MulkCMS newsletter because we
+received an unsubscription request from your email address.
+
+To register for the newsletter again, open the following page in
+your web browser:
+
+  https://matthias.benkard.de/newsletter