[vsphere][zonal] Multi-zone installations with cluster-bot

*USER STORY:*

As an OpenShift engineer, I want quickly provision an OpenShift cluster on vSphere in a multi-zonal fashion so that I can save time performing installations.

*DESCRIPTION:*

Cluster bot needs to be able to install OpenShift on vSphere using multi-zone.

Something like this in Slack...

launch 4.12 vsphere-zones

*Required:*

• New platform option (in Slack) for cluster bot to launch in vsphere zones
• Any new configurations required in openshift/release
• New resources in IBMCloud vSphere to handle clusterbot load

*ACCEPTANCE CRITERIA:*

• Can successfully install vSphere multi-zone OpenShift cluster via Slack
• Provisioning through clusterbot does not interfere with CI