feat: implement anvil_ pool manipulation API endpoints

[itegulov]

Need to implement three endpoints from anvil for manipulating transaction pool:

#[rpc(name = "anvil_dropTransaction")]
fn drop_transaction(&self, tx_hash: H256) -> RpcResult<Option<H256>>;

#[rpc(name = "anvil_dropAllTransactions")]
fn drop_all_transactions(&self) -> RpcResult<()>;

#[rpc(name = "anvil_removePoolTransactions")]
fn remove_pool_transactions(&self, address: Address) -> RpcResult<()>;

Requires #362

See https://github.com/matter-labs/era-test-node/issues/148 for a matching hardhat method