Send mail to users when the note balance is negative

templates/registration/mails/email_validation_email.txt

@@ -0,0 +1,16 @@
+{% load i18n %}
+
+{% trans "Hi" %} {{ user.username }},
+
+{% trans "You recently registered on the Note Kfet. Please click on the link below to confirm your registration." %}
+
+https://{{ domain }}{% url 'registration:email_validation' uidb64=uid token=token %}
+
+{% trans "This link is only valid for a couple of days, after that you will need to contact us to validate your email." %}
+
+{% trans "After that, you'll have to wait that someone validates your account before you can log in. You will need to pay your membership in the Kfet." %}
+
+{% trans "Thanks" %},
+
+{% trans "The Note Kfet team." %}
+Mail généré par la Note Kfet le {% now "j F Y à H:i:s" %}