Fully support dropwizard metrics in beam and runners

As proposed at https://docs.google.com/document/d/1-35iyCIJ9P4EQONlakgXBFRGUYoOLanq2Uf2sw5EjJw/edit?usp=sharing , I'd like to add full support of dropwizard metrics by delegating beam metrics to runners.

The proposal involves a few subtasks, as far as I see, including:
1. add Meter interface in sdk-java-core and extend Distribution to support quantiles
2. add MeterData, extend DistributionData. Merge {Counter/Meter/Gauge/Distribution}Data instead of Counter/Meter/Gauge/Distribution at accumulators.
3. Runner changes over improved metrics.

I will create subtasks later if there's no objection.

Imported from Jira [BEAM-2602](https://issues.apache.org/jira/browse/BEAM-2602). Original Jira may contain additional context.
Reported by: Cody.

Start with the linked proposal, then inspect sdk-java-core and the named Meter, Distribution, MeterData, and DistributionData components, along with accumulator and runner code. Done means the listed metric types are supported through the SDK, accumulators, and runners, including quantiles and runner delegation.

Written by the indexing model from the issue text.