Build a tool that can easily port data on Druid to Pinot

Many clients are interested in comparing the performance between Pinot and Druid for their use cases. We have seen many cases where clients are already running Druid cluster. If we provided a tool that can easily migrate data from Druid cluster to Pinot cluster, people can compare two systems more easily and we will also be able to gain more adoption.

This will involve in implementing the following components:
1. Druid Segment Reader
2. Druid-Pinot Segment conversion tool & Hadoop job
3. Schema & Table config converter

This can be extended to a tool that automatizes the end-to-end migration process.