Add latest_interior_ref_list_by_shop_id endpoint

Not sure if this is correct yet, still waiting for rustc to compile...

src/caches/mod.rs

@@ -20,6 +20,7 @@ pub struct Caches {
     pub list_owners: Cache<ListParams, CachedResponse>,
     pub list_interior_ref_lists: Cache<ListParams, CachedResponse>,
     pub list_merchandise_lists: Cache<ListParams, CachedResponse>,
+    pub latest_interior_ref_list_by_shop_id: Cache<i32, CachedResponse>,
 }
 
 impl Caches {
@@ -34,6 +35,10 @@ impl Caches {
             list_owners: Cache::new("list_owners", 100),
             list_interior_ref_lists: Cache::new("list_interior_ref_lists", 100),
             list_merchandise_lists: Cache::new("list_merchandise_lists", 100),
+            latest_interior_ref_list_by_shop_id: Cache::new(
+                "latest_interior_ref_list_by_shop_id",
+                100,
+            ),
         }
     }
 }