* Run -race for go test
* Upgrade go 1.15.3
* Extract a function to create rados connection
* Convert to go module; update dependencies
* Use environment variables to pass in parameters
* Make rados connection short lived
* Use float64 for JSON number in cluster_usage.go
* Use mocks to replace the NoopConn
* Add "-tags nautilus" for "go test" and "go build"
* Update readme
* Update go mod
