make deprecation warnings at /api/ much more obvious

awx/templates/rest_framework/base.html

@@ -73,6 +73,11 @@
 
         <!-- Content -->
         <div id="content" role="main" aria-label="{% trans "content" %}">
+          {% if deprecated %}
+            <div class="breadcrumb" style="background: #FCC;">
+                <b>This resource has been deprecated and will be removed in a future release.</b>
+            </div>
+          {% endif %}
           {% block content %}
 
           <div class="region"  aria-label="{% trans "request form" %}">