Move `ShardStateServices` into blueflood-core.
import/comment cleanup
Bugfix in ShardStateServices
* was not getting started properly.
make a few things public in `RollupService` and `ScheduleContext`.
Hook a few more things into the Carbon ingestor.
Add a context updater for this environment.
Move `StatType` into blueflood-core.
More generic write-rollup methods in `AstyanaxWriter`.

* allow `Rollup` instead of `BasicRollup`.
rollup differently serialized metrics

* LocatorFetchRunnable no longer cares about src- and dst- column families.
* RollupContext simplified to refer to source granularity instead of column families
* RollupRunnable now decides which columnfamiles to read/write from/to and also computes the serializer to use.