* Add chainID flag and make chainConfig optional
* Add prometheus metrics to monitor validation progress
* Make writeStateDiffAt calls on missing blocks
* Update docs and config improvements
* Use standard logger
* Add copyright to files
* Upgrade dependencies
* Add checks to validate referential integrity
* Add unit tests for referential integrity validation
* Use EXISTS in referential integrity validation queries
* Make validation process perpetual
* Get sleep interval from config
* Add license
* Gracefully shutdown validator on interrupt
* Change default trail and sleep values