feat: create DRF endpoint to get course index context (#33667)

* feat: create DRF endpoint to get course index context

* refactor: update serializers location and added some tests

* refactor: move modulestore usage out of views

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Co-authored-by: ruzniaievdm <ruzniaievdm@gmail.com>

cms/djangoapps/contentstore/rest_api/serializers/common.py

@@ -50,3 +50,23 @@ class StrictSerializer(serializers.Serializer):
                 )
 
         return ret
+
+
+class ProctoringErrorModelSerializer(serializers.Serializer):
+    """
+    Serializer for proctoring error model item.
+    """
+    deprecated = serializers.BooleanField()
+    display_name = serializers.CharField()
+    help = serializers.CharField()
+    hide_on_enabled_publisher = serializers.BooleanField()
+    value = serializers.CharField()
+
+
+class ProctoringErrorListSerializer(serializers.Serializer):
+    """
+    Serializer for proctoring error list.
+    """
+    key = serializers.CharField()
+    message = serializers.CharField()
+    model = ProctoringErrorModelSerializer()