add Stanford-specific embargo message

templates/static_templates/theme-embargo.html

@@ -0,0 +1,13 @@
+<%! from django.utils.translation import ugettext as _ %>
+<%inherit file="../main.html" />
+
+<%block name="pagetitle">${_("This Course Unavailable In Your Country")}</%block>
+
+<section class="outside-app">
+<p>${_("Our system indicates that you are trying to access a course at class.stanford.edu from an " +
+       "IP address associated with a country currently subject to comprehensive U.S. " +
+       "economic and trade sanctions.  Stanford University is required to comply with " +
+       "these sanctions regulations, and regretfully, we are not permitted to allow you " +
+       "to access this particular course.  Feel free to browse our catalogue to find other " +
+       "courses you may be interested in taking.")}</p>
+</section>