Ability to deploy OpenStack in auto mode

New features added:
1. You can add new slave nodes separately, after fuel-master node deployment.
2. Generate and Deploy SSH key on fuel-master
2. You can work with fuel over CLI using exec_on_fuel_master()
3. You can deploy OpenStack cluster in automatic mode:

Usage: ./launch.sh {deploy|add-slave [number of slaves] | deploy-openstack}

deploy – install fuel-master and run 3 slave nodes
add-slave – add and start new slave node (ONE by default), but can be more.
deploy-openstack – deploy OpenStack with parameters defined in config.sh

Example:
	ENV_NAME="MyEnv2"
	ENV_RELEASE=1 # centos
	MODE="multinode"
	OS_CLUSTER="controller,cinder|compute|compute"

Script will automatically check for compatibility between roles (currently full support for multinode mode) and Free nodes availability