Add component controller inheritance and new inputs

awx/ui/client/lib/theme/_mixins.less

@@ -10,6 +10,16 @@
     }
 }
 
+.at-mixin-Heading (@size) {
+    color: @at-gray-dark-4x;
+    font-size: @size;
+    font-weight: @at-font-weight-2x;
+    line-height: @at-line-height-short;
+    text-transform: uppercase;
+    margin: 0;
+    padding: 0;
+}
+
 .at-mixin-Button () {
     padding: @at-space-2x @at-space-4x;
 }