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/system/src/migration.rs

@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: 2023 Snowfork <hello@snowfork.com>
+//! Governance API for controlling the Ethereum side of the bridge
+use super::*;
+use frame_support::traits::OnRuntimeUpgrade;
+use log;
+
+#[cfg(feature = "try-runtime")]
+use sp_runtime::TryRuntimeError;
+
+pub mod v0 {
+	use frame_support::{pallet_prelude::*, weights::Weight};
+
+	use super::*;
+
+	const LOG_TARGET: &str = "ethereum_system::migration";
+
+	pub struct InitializeOnUpgrade<T, BridgeHubParaId, AssetHubParaId>(
+		sp_std::marker::PhantomData<(T, BridgeHubParaId, AssetHubParaId)>,
+	);
+	impl<T, BridgeHubParaId, AssetHubParaId> OnRuntimeUpgrade
+		for InitializeOnUpgrade<T, BridgeHubParaId, AssetHubParaId>
+	where
+		T: Config,
+		BridgeHubParaId: Get<u32>,
+		AssetHubParaId: Get<u32>,
+	{
+		fn on_runtime_upgrade() -> Weight {
+			if !Pallet::<T>::is_initialized() {
+				Pallet::<T>::initialize(
+					BridgeHubParaId::get().into(),
+					AssetHubParaId::get().into(),
+				)
+				.expect("infallible; qed");
+				log::info!(
+					target: LOG_TARGET,
+					"Ethereum system initialized."
+				);
+				T::DbWeight::get().reads_writes(2, 5)
+			} else {
+				log::info!(
+					target: LOG_TARGET,
+					"Ethereum system already initialized. Skipping."
+				);
+				T::DbWeight::get().reads(2)
+			}
+		}
+
+		#[cfg(feature = "try-runtime")]
+		fn pre_upgrade() -> Result<Vec<u8>, TryRuntimeError> {
+			if !Pallet::<T>::is_initialized() {
+				log::info!(
+					target: LOG_TARGET,
+					"Agents and channels not initialized. Initialization will run."
+				);
+			} else {
+				log::info!(
+					target: LOG_TARGET,
+					"Agents and channels are initialized. Initialization will not run."
+				);
+			}
+			Ok(vec![])
+		}
+
+		#[cfg(feature = "try-runtime")]
+		fn post_upgrade(_: Vec<u8>) -> Result<(), TryRuntimeError> {
+			frame_support::ensure!(
+				Pallet::<T>::is_initialized(),
+				"Agents and channels were not initialized."
+			);
+			Ok(())
+		}
+	}
+}