Cleanup light client leftovers (#1456)

* Cleanup light client leftovers

* Readme: make it clear that Collator is full node of parachain

* cargo update -p sp-io

* cargo update -p polkadot-primitives

test/service/src/lib.rs

@@ -227,10 +227,6 @@ pub async fn start_node_impl<RB>(
 where
 	RB: Fn(Arc<Client>) -> Result<jsonrpsee::RpcModule<()>, sc_service::Error> + Send + 'static,
 {
-	if matches!(parachain_config.role, Role::Light) {
-		return Err("Light client not supported!".into())
-	}
-
 	let mut parachain_config = prepare_node_config(parachain_config);
 
 	let params = new_partial(&mut parachain_config)?;