Changelog
Added Helm Charts for deploying zookeeper and zookeeper-operator
Added Helm Test functionality for zookeeper.
Upgraded zookeeper base image from 3.5.4-beta to 3.5.5
Fixed the default zookeeper image used by operator to point to pravega/zookeeper:latest
Upgraded golang version from 1.10 to 1.12, as without this Windows cross-compilation had started failing due to changes to golang libraries.