Nfts attribute read interface (#13349)

* feat: add custom and system attributes to Inspect

* feat: add nfts runtime api

* fix: pass std feature to runtime api

* fix: api copyright

Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>

---------

Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>

substrate/frame/nfts/runtime-api/src/lib.rs

@@ -0,0 +1,57 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2023 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Runtime API definition for the FRAME NFTs pallet.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use codec::{Decode, Encode};
+use frame_support::dispatch::Vec;
+
+sp_api::decl_runtime_apis! {
+	pub trait NftsApi<AccountId, CollectionId, ItemId>
+	where
+		AccountId: Encode + Decode,
+		CollectionId: Encode,
+		ItemId: Encode,
+	{
+		fn owner(collection: CollectionId, item: ItemId) -> Option<AccountId>;
+
+		fn collection_owner(collection: CollectionId) -> Option<AccountId>;
+
+		fn attribute(
+			collection: CollectionId,
+			item: ItemId,
+			key: Vec<u8>,
+		) -> Option<Vec<u8>>;
+
+		fn custom_attribute(
+			account: AccountId,
+			collection: CollectionId,
+			item: ItemId,
+			key: Vec<u8>,
+		) -> Option<Vec<u8>>;
+
+		fn system_attribute(
+			collection: CollectionId,
+			item: ItemId,
+			key: Vec<u8>,
+		) -> Option<Vec<u8>>;
+
+		fn collection_attribute(collection: CollectionId, key: Vec<u8>) -> Option<Vec<u8>>;
+	}
+}