BRIDGE: add asset pallet

[p5150j]

Description
In order to teleport Frequency tokens to AssetHub, we need a way to pay the execution fee on AssetHub otherwise it will reject the request and treat the tokens as trapped assets.

Since AssetHub does not accept Frequency as payment for execution fees, we must also include DOT in the message to cover those fees.

To support this, Frequency must be able to handle DOT as an asset — both to receive DOT from AssetHub and to send DOT back out.

Acceptance Criteria

• Add the ability to send and receive DOT on Frequency
• Store DOT as a Multilocation on Frequency
• Decide who should be allowed to create assets on Frequency
• Generate Weights
• Feature Flag Bridging

Implementation suggestions

• User Pallet Assets
• Config

pallet-assets = { workspace = true, default-features = false }
assets-common = { workspace = true, default-features = false }

parameter_types! {
	pub const AssetDeposit: Balance = 0;
	pub const AssetAccountDeposit: Balance = 0;
	pub const ApprovalDeposit: Balance = 0;
	pub const AssetsStringLimit: u32 = 50;
	pub const MetadataDepositBase: Balance = 0;
	pub const MetadataDepositPerByte: Balance = 0;
}

parameter_types! {
	// we just reuse the same deposits
	pub const ForeignAssetsAssetDeposit: Balance = AssetDeposit::get();
	pub const ForeignAssetsAssetAccountDeposit: Balance = AssetAccountDeposit::get();
	pub const ForeignAssetsApprovalDeposit: Balance = ApprovalDeposit::get();
	pub const ForeignAssetsAssetsStringLimit: u32 = AssetsStringLimit::get();
	pub const ForeignAssetsMetadataDepositBase: Balance = MetadataDepositBase::get();
	pub const ForeignAssetsMetadataDepositPerByte: Balance = MetadataDepositPerByte::get();
}

use xcm_config::{RelayLocation, XcmOriginToTransactDispatchOrigin, ForeignAssetsAssetId};
impl pallet_assets::Config  for Runtime {
	type RuntimeEvent = RuntimeEvent;
	type Balance = Balance;
////
	type AssetId = ForeignAssetsAssetId;
	type AssetIdParameter = ForeignAssetsAssetId;
	type Currency = Balances;
	// This is to allow any other remote location to create foreign assets. Used in tests, not
	// recommended on real chains.
	type **CreateOrigin** =
		**ForeignCreators**<Everything, LocationToAccountId, AccountId, xcm::latest::Location>;
	type ForceOrigin = EnsureRoot<AccountId>;
	type AssetDeposit = ForeignAssetsAssetDeposit;
	type MetadataDepositBase = ForeignAssetsMetadataDepositBase;
	type MetadataDepositPerByte = ForeignAssetsMetadataDepositPerByte;
	type ApprovalDeposit = ForeignAssetsApprovalDeposit;
	type StringLimit = ForeignAssetsAssetsStringLimit;
	type Freezer = ();
	type Extra = ();
	type WeightInfo = pallet_assets::weights::SubstrateWeight<Runtime>;
	type CallbackHandle = ();
	type AssetAccountDeposit = ForeignAssetsAssetAccountDeposit;
	type RemoveItemsLimit = frame_support::traits::ConstU32<1000>;
	#[cfg(feature = "runtime-benchmarks")]
	type BenchmarkHelper = xcm_config::XcmBenchmarkHelper;
	type Holder = ();
}