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/bookshelf/views.py

@@ -1,12 +1,14 @@
 from rest_framework.generics import ListAPIView, RetrieveAPIView
 from rest_framework.schemas.openapi import AutoSchema
 
+from ram.views import CustomLimitOffsetPagination
 from bookshelf.models import Book, Catalog
 from bookshelf.serializers import BookSerializer, CatalogSerializer
 
 
 class BookList(ListAPIView):
     serializer_class = BookSerializer
+    pagination_class = CustomLimitOffsetPagination
 
     def get_queryset(self):
         return Book.objects.get_published(self.request.user)
@@ -23,6 +25,7 @@ class BookGet(RetrieveAPIView):
 
 class CatalogList(ListAPIView):
     serializer_class = CatalogSerializer
+    pagination_class = CustomLimitOffsetPagination
 
     def get_queryset(self):
         return Catalog.objects.get_published(self.request.user)