Refactoring vanilla 2 plugin

Separation vanilla 2 plugin in two parts:
* version specific code (configs)
* common code (provisioning, scaling, validation, etc...)

This patch needed to support various hadoop versions

Partially implements blueprint: add-vanilla-2-hadoop-2-4-0

Change-Id: I41678aed2bfb767c04af8bd52d28cd265fa125d7
Merge "Refactoring vanilla 2 plugin"