Add WASM CI checks and make availability-store compile for WASM (#626)

* Make availability-store compile for WASM

* Use --manifest-path instead

polkadot/availability-store/src/lib.rs

@@ -22,7 +22,6 @@
 
 use codec::{Encode, Decode};
 use kvdb::{KeyValueDB, DBTransaction};
-use kvdb_rocksdb::{Database, DatabaseConfig};
 use polkadot_primitives::Hash;
 use polkadot_primitives::parachain::{Id as ParaId, BlockData, Message};
 use log::warn;
@@ -74,7 +73,9 @@ pub struct Store {
 
 impl Store {
 	/// Create a new `Store` with given config on disk.
+	#[cfg(not(target_os = "unknown"))]
 	pub fn new(config: Config) -> io::Result<Self> {
+		use kvdb_rocksdb::{Database, DatabaseConfig};
 		let mut db_config = DatabaseConfig::with_columns(Some(columns::NUM_COLUMNS));
 
 		if let Some(cache_size) = config.cache_size {