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/scripts/init.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+set -e
+
+echo "*** Initializing WASM build environment"
+
+if [ -z $CI_PROJECT_NAME ] ; then
+   rustup update nightly
+   rustup update stable
+fi
+
+rustup target add wasm32-unknown-unknown --toolchain nightly