Add REST API pagination and mke REST API optional (#43)

* Implement Rest API pagination

* REST API must be enabled in settings

* Report REST API status in the admin site settings page

ram/consist/views.py

@@ -1,11 +1,13 @@
 from rest_framework.generics import ListAPIView, RetrieveAPIView
 
+from ram.views import CustomLimitOffsetPagination
 from consist.models import Consist
 from consist.serializers import ConsistSerializer
 
 
 class ConsistList(ListAPIView):
     serializer_class = ConsistSerializer
+    pagination_class = CustomLimitOffsetPagination
 
     def get_queryset(self):
         return Consist.objects.get_published(self.request.user)