### Summary
This pull request adds the source code from https://github.com/XLabs/influx-backfiller to this repository.
Also, several changes have been made to the InfluxDB backfiller:
* Stop using floats to store/manipulate price data, use decimals or integers instead.
* Update the volume metric to be in sync with the rest of the codebase.
* Remove duplicated code between the influx backfiller and analytics modules.
* Remove a fair amount of unused code