Provide a way to set DistributionSummary config via builder

[minwoox]

Users need to use MoreMeters.setDistributionStatisticConfig(config) to specify the distribution config.
That means users cannot configure different configs depending on the client. Using the static class is also not intuitive and not the Armeria style which uses a builder for setting configuration.
We can probably do:

MetricCollectingClient.builder(meterIdPrefixFunction)
  .distributionStatisticConfig(config)
  ...

We can also add the getter to FlagsProvider:

public interface FlagsProvider {
  default DistributionStatisticConfig distributionStatisticConfig() { return null;}
}

[echo304]

I will take this issue :) ✋