* IT: Switch to OpenJDK8 base image.
Also split the Docker image into a base image and a child image, and
build the base image ahead of time for efficiency's sake. Also upgrade
ZK to 3.4.10.
* Additional comments about ZK upgrades.
* Use OpenJDK8 instead of Oracle for IT docker
* install wget
* Use different docker image
* Revert "Use different docker image"
This reverts commit 5786c03cb49d0ac60a4f06690e483c3284fe4564.
* Revert "install wget"
This reverts commit 8d1d5ec681301f2919b9d994e65e4d436f948a72.
* Revert "Use OpenJDK8 instead of Oracle for IT docker"
This reverts commit 55ea163bb530b1e88c2cccd647f89d75ac90393a.
* Use prebuilt java8 image
* Add comment on docker image
* Remove DruidProcessingModule, QueryableModule and QueryRunnerFactoryModule from DI for coordinator, overlord, middle-manager. Add RouterDruidProcessing not to allocate processing resources on router
* Fix examples
* Fixes
* Revert Peon configs and add comments
* Remove qualifier
ITUnionQueryTest runs 4 realtime tasks and runs a unionQuery over them,
the worker is not able to run all the tasks concurrently on machines
with less cpu cores as it picks default worker capacity.
Explicitly specify worker capacity to avoid this.