[ui][registration][template] Fix activate message for supervisor

The current message was the same for everybody.

Fixes #490

beat/web/ui/registration/templates/registration/activate.html

@@ -30,10 +30,16 @@
 
     {% if account %}
     <p class="text">Your account is almost activated. Welcome {{ account.username }}.
+    {% if account.profile.is_supervisor %}
+    We have received your request and the administrators are currently validating
+    your candidature. You will be informed by email once this is done.
+    {% else %}
     We have asked your "supervisor" to validate your account and accept you as a
     supervisee. You will be informed by email once this is done.
     In the meantime you can remind your "supervisor" to validate
-    your account. You will then be able to  <a href="{% url 'login' %}">sign in</a> and start your own experiments!</p>
+    your account.
+    {% endif %}
+    You will then be able to  <a href="{% url 'login' %}">sign in</a> and start your own experiments!</p>
     {% else %}
     <p class="text">Your account wasn't activated. Check that the URL you entered is correct.
     If you already clicked on the link sent to you by email, you need to wait