Westend: Fellowship Treasury (#2532)

Treasury Pallet Instance for the Fellowship in Westend Collectives.

In this update, we present a Treasury Pallet Instance that is under the
control of the Fellowship body, with oversight from the Root and
Treasurer origins. Here's how it is governed:
- the Root origin have the authority to reject or approve spend
proposals, with no amount limit for approvals.
- the Treasurer origin have the authority to reject or approve spend
proposals, with approval limits of up to 10,000,000 DOT.
- Voice of all Fellows ranked at 3 or above can reject or approve spend
proposals, with a maximum approval limit of 10,000 DOT.
- Voice of Fellows ranked at 4 or above can also reject or approve spend
proposals, with a maximum approval limit of 10,000,000 DOT.

Additionally, we introduce the Asset Rate Pallet Instance to establish
conversion rates from asset A to B. This is used to determine if a
proposed spend amount involving a non-native asset is permissible by the
commanding origin. The rates can be set up by the Root, Treasurer
origins, or Voice of all Fellows.

---------

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

polkadot/runtime/common/src/impls.rs

@@ -149,8 +149,11 @@ impl TryConvert<&VersionedMultiLocation, xcm::latest::MultiLocation>
 #[cfg(feature = "runtime-benchmarks")]
 pub mod benchmarks {
 	use super::VersionedLocatableAsset;
+	use core::marker::PhantomData;
+	use frame_support::traits::Get;
 	use pallet_asset_rate::AssetKindFactory;
 	use pallet_treasury::ArgumentsFactory as TreasuryArgumentsFactory;
+	use sp_core::{ConstU32, ConstU8};
 	use xcm::prelude::*;
 
 	/// Provides a factory method for the [`VersionedLocatableAsset`].
@@ -172,12 +175,22 @@ pub mod benchmarks {
 	/// Provide factory methods for the [`VersionedLocatableAsset`] and the `Beneficiary` of the
 	/// [`VersionedMultiLocation`]. The location of the asset is determined as a Parachain with an
 	/// ID equal to the passed seed.
-	pub struct TreasuryArguments;
-	impl TreasuryArgumentsFactory<VersionedLocatableAsset, VersionedMultiLocation>
-		for TreasuryArguments
+	pub struct TreasuryArguments<Parents = ConstU8<0>, ParaId = ConstU32<0>>(
+		PhantomData<(Parents, ParaId)>,
+	);
+	impl<Parents: Get<u8>, ParaId: Get<u32>>
+		TreasuryArgumentsFactory<VersionedLocatableAsset, VersionedMultiLocation>
+		for TreasuryArguments<Parents, ParaId>
 	{
 		fn create_asset_kind(seed: u32) -> VersionedLocatableAsset {
-			AssetRateArguments::create_asset_kind(seed)
+			VersionedLocatableAsset::V3 {
+				location: xcm::v3::MultiLocation::new(Parents::get(), X1(Parachain(ParaId::get()))),
+				asset_id: xcm::v3::MultiLocation::new(
+					0,
+					X2(PalletInstance(seed.try_into().unwrap()), GeneralIndex(seed.into())),
+				)
+				.into(),
+			}
 		}
 		fn create_beneficiary(seed: [u8; 32]) -> VersionedMultiLocation {
 			VersionedMultiLocation::V3(xcm::v3::MultiLocation::new(