RPC: parity_allTransactionHashes (#9745)

* rpc: add parity_allTransactionHashes

* Add light_all_transactionst to helpers

* Remove extra parentheses

* Move light_all_transactions to light_fetch

* Remove LightDispatcher import in light_fetch

miner/src/pool/queue.rs

@@ -315,6 +315,12 @@ impl TransactionQueue {
 		self.pool.read().unordered_pending(ready).collect()
 	}
 
+	/// Returns all transaction hashes in the queue without explicit ordering.
+	pub fn all_transaction_hashes(&self) -> Vec<H256> {
+		let ready = |_tx: &pool::VerifiedTransaction| txpool::Readiness::Ready;
+		self.pool.read().unordered_pending(ready).map(|tx| tx.hash).collect()
+	}
+
 	/// Computes unordered set of pending hashes.
 	///
 	/// Since strict nonce-checking is not required, you may get some false positive future transactions as well.