* First Heron-Dhalion commit to enable topology auto-health-management

* Add dhalion dependencies
* Build and deploy health manager library
* Add utility class to pull metrics from tracker

* Connect PackingPlan and Topology providers to the StateMgr

* Minor refactor for readability

* Refactor code to use latest dhalion api

* Add health policy config yaml

* Add Heron main class for HealthManager

* Fix any issues running HealthManager as a process

* Assume all health policy configs to be strings

* Isolate policy config specific guice modules

* Add event handlers and invoke resolver actions

* Fix dhalion package name change related errros

* Use JsonPath to parse tracker response

* Add bazel dependencies for json path

* Replace tracker's metrics call with timeline call

* Fix checkstyle errors

* Use the Dhalion project's repo as binary source

* Update dependencies as per update heron-common

* Mark HealthManager evolving, remove dead code, improve javadoc

* Add sample config file for the HealthManager

* Address review comment, use ConfigReader for yaml files

* Fix checkstyle errors

* Decouple HealthManager constructor and tracker

Resolves a review comment

* Remove interface for constants

* Rename healthm so that it matches other components

* Address review comments

* Add dependency on full proto package instead of sub package
* Refactor method consuming command line arguments

* Avoid building health manager package

Wait for the dhalion jar to be available on maven central before
enabling health manager. Also fix healthmgr path in build scripts

* Address review comments