Allow user to Stop Deployment and further Restart it

As an Operator I want to be able to Stop Deployment and Restart it so that I could address the reasons for stopping and proceed with deployment process to cover situations when Operator discovers something that's about to prevent success of cloud deployment and now needs to address it. Examples are:

    Some nodes failed during OS provisioning (on yet unknown reasons)
    Some nodes became "gone" during deployment (loss of network connectivity, etc)
    Operator discovers the need to adjust deployment settings (networks, plugins, enabled services, etc)

For all cases of such kind the following UX must be made available:

    User faces the case when cloud deployment needs to be stopped and some measures taken to assure it's further success
    User presses "Stop deployment" button
    User makes changes required to prevent failure - fixes the servers, makes changes in deployment config parameters, etc
    User presses "Restart deployment" button
    Fuel proceeds with cloud deployment, based on the stage that particular node was able to get into (OS provisioned, OpenStack deploying), with necessary tasks being re-ran on particular nodes