[NFTs] Track item's metadata depositor (#13124)

* Refactor do_mint()

* Track the depositor of item's metadata

* Revert back the access control

* On collection destroy return the metadata deposit

* Clear the metadata on item burn returning the deposit

* Address comments

* Fix clippy

* Don't return Ok on non-existing attribute removal

substrate/frame/nfts/src/lib.rs

@@ -263,7 +263,7 @@ pub mod pallet {
 		T::CollectionId,
 		Blake2_128Concat,
 		T::ItemId,
-		ItemMetadata<DepositBalanceOf<T, I>, T::StringLimit>,
+		ItemMetadata<ItemMetadataDepositOf<T, I>, T::StringLimit>,
 		OptionQuery,
 	>;
 
@@ -559,6 +559,10 @@ pub mod pallet {
 		UnknownItem,
 		/// Swap doesn't exist.
 		UnknownSwap,
+		/// The given item has no metadata set.
+		MetadataNotFound,
+		/// The provided attribute can't be found.
+		AttributeNotFound,
 		/// Item is not for sale.
 		NotForSale,
 		/// The provided bid is too low.
@@ -746,10 +750,9 @@ pub mod pallet {
 			Self::do_mint(
 				collection,
 				item,
-				caller.clone(),
+				Some(caller.clone()),
 				mint_to.clone(),
 				item_config,
-				false,
 				|collection_details, collection_config| {
 					// Issuer can mint regardless of mint settings
 					if Self::has_role(&collection, &caller, CollectionRole::Issuer) {
@@ -849,9 +852,7 @@ pub mod pallet {
 					Error::<T, I>::NoPermission
 				);
 			}
-			Self::do_mint(collection, item, mint_to.clone(), mint_to, item_config, true, |_, _| {
-				Ok(())
-			})
+			Self::do_mint(collection, item, None, mint_to, item_config, |_, _| Ok(()))
 		}
 
 		/// Destroy a single item.
@@ -1362,7 +1363,7 @@ pub mod pallet {
 		/// Clear an attribute for a collection or item.
 		///
 		/// Origin must be either `ForceOrigin` or Signed and the sender should be the Owner of the
-		/// `collection`.
+		/// attribute.
 		///
 		/// Any deposit is freed for the collection's owner.
 		///
@@ -1464,7 +1465,7 @@ pub mod pallet {
 			let maybe_check_owner = T::ForceOrigin::try_origin(origin)
 				.map(|_| None)
 				.or_else(|origin| ensure_signed(origin).map(Some).map_err(DispatchError::from))?;
-			Self::do_set_item_metadata(maybe_check_owner, collection, item, data)
+			Self::do_set_item_metadata(maybe_check_owner, collection, item, data, None)
 		}
 
 		/// Clear the metadata for an item.