Add is_active_for_store() method to products handler

with some basic logic, which assumes a volatile cache table has
accurate data...

rattail/products.py

@@ -594,6 +594,16 @@ class ProductsHandler(GenericHandler):
 
         return get_product_by_code(session, entry)
 
+    def is_active_for_store(self, product, store, **kwargs):
+        """
+        Return boolean indicating whether the given product is
+        considered "active" at the given store.
+        """
+        info = product.store_infos.get(store.uuid)
+        if info and info.recently_active:
+            return True
+        return False
+
     def normalize_product(self, product, fields=None, **kwargs):
         """
         Normalize the given product to a JSON-serializable dict.