eth_getTransactionCount high latency

Hi @splix , we're consistently seeing `eth_getTransactionCount` response times of above 500ms, while the same call to geth takes 50ms. We tried disabling the call for nodes outside the LB region but it didn't make a big difference.

https://github.com/emeraldpay/dshackle/blob/master/src/main/kotlin/io/emeraldpay/dshackle/upstream/calls/DefaultEthereumMethods.kt#L97

Looks like `NonceQuorum` needs to confirm with at least 3 upstreams before responding, would it be possible to make this configurable or change it to something more sensible like `NotLaggingQuorum(0)` ? so it's consistent with `eth_getBalance` and `eth_blockNumber`.