Return error if RLP size of transaction exceeds the limit (#8473)

* Return error if RLP size of transaction exceeds the limit

* Review comments fixed

* RLP check moved to verifier, corresponding pool test added

json/src/spec/params.rs

@@ -113,6 +113,9 @@ pub struct Params {
 	/// See main EthashParams docs.
 	#[serde(rename="maxCodeSize")]
 	pub max_code_size: Option<Uint>,
+	/// Maximum size of transaction RLP payload.
+	#[serde(rename="maxTransactionSize")]
+	pub max_transaction_size: Option<Uint>,
 	/// See main EthashParams docs.
 	#[serde(rename="maxCodeSizeTransition")]
 	pub max_code_size_transition: Option<Uint>,