feat: implement anvil_dumpState/anvil_loadState API endpoints

[itegulov]

We can likely reuse snapshot logic for this. Ideally #414 should be done before this is worked on to avoid changes in serialization format (although likely we don't want to provide any cross-version guarantees here).

#[rpc(name = "anvil_dumpState")]
fn dump_state(&self, preserve_historical_states: Option<bool>) -> RpcResult<Bytes>;

#[rpc(name = "anvil_loadState")]
fn load_state(&self, bytes: Bytes) -> RpcResult<bool>;