Make repartitioner interface consistent + cleanup
More cleanup to repartitioner

Fix varible names, typos add comments
Rename new cluster script
Copy analysis file to output_dir
Fix NPE in the test code

Pass an empty list instead of a null.
Drop KeyDistributionGenerator and Entropy

The intended usage of KeyDistributionGenerator and Entropy has been replaced. The PartitionAnalysisCLI and PartitionBalance tools replace the 'skew' estimation functionality of these tools. The KeySampler and KeyVerionFetcher replace the verification functionality of the EntropyChecker.

The helper method KeyDistributionGenerator.getUniqueStoreDefinitionsWithCounts has moved to StoreDefinitionUtils.getUniqueStoreDefinitionsWithCounts.
Complete dropping KeyDistributionGenerator