Removes Snowbridge parachain directory (#3186)

Removes the `bridges/snowbridge/parachain` directory and moves
everything up to under `snowbridge` directly. We are cleaning up our
local dev env after merging our crates into the polkadot-sdk.

---------

Co-authored-by: claravanstaden <Cats 4 life!>

bridges/snowbridge/pallets/outbound-queue/src/api.rs

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: 2023 Snowfork <hello@snowfork.com>
+//! Helpers for implementing runtime api
+
+use crate::{Config, MessageLeaves};
+use frame_support::storage::StorageStreamIter;
+use snowbridge_core::outbound::{Message, SendMessage};
+use snowbridge_outbound_queue_merkle_tree::{merkle_proof, MerkleProof};
+
+pub fn prove_message<T>(leaf_index: u64) -> Option<MerkleProof>
+where
+	T: Config,
+{
+	if !MessageLeaves::<T>::exists() {
+		return None
+	}
+	let proof =
+		merkle_proof::<<T as Config>::Hashing, _>(MessageLeaves::<T>::stream_iter(), leaf_index);
+	Some(proof)
+}
+
+pub fn calculate_fee<T>(message: Message) -> Option<T::Balance>
+where
+	T: Config,
+{
+	match crate::Pallet::<T>::validate(&message) {
+		Ok((_, fees)) => Some(fees.total()),
+		_ => None,
+	}
+}