Add a common base email template, translate the emails over to using jinja and add emails when e-mail addresses and passwords are changed.

emails/passwordchanged.html

@@ -0,0 +1,12 @@
+{% extends "base.html" %}
+
+{% block content %}
+
+<h3>Account Password Changed</h3>
+
+The password for user {{ username | user_reference }} has been updated.
+<br>
+<br>
+If this change was not expected, please immediately log into your {{ username | admin_reference }} and reset your password.
+
+{% endblock %}