Only show cohort config for cohorted courses

lms/templates/course_groups/cohort_management.html

 <section class="cohort_manager" data-ajax_url="${cohorts_ajax_url}">
 <h3>Cohort groups</h3>
 
-<div class="controls">
+<div class="controls" style="padding-top:15px">
   <a href="#" class="button show_cohorts">Show cohorts</a>
 </div>
 

lms/templates/courseware/instructor_dashboard.html

@@ -285,7 +285,9 @@ function goto( mode)
     </p>
     <hr width="40%" style="align:left">
 
+    %if course.is_cohorted:
     <%include file="/course_groups/cohort_management.html" />
+    %endif
 
   %endif
 %endif