SPLAT-2238: Cleaned up vSphere zonal jobs from using hard coded pools

[vr4manta]

SPLAT-2238

Changes

• Enhanced core ipi vcm config step to handle generating zone blocks in install-config
• Deprecated zonal step
• Increased zonal job's FD to be 4 so that we can have extra for special e2e tests
• Limit all jobs by default to 3 vCenters in lease request

Summary by CodeRabbit

This PR updates OpenShift CI’s vSphere IPI configuration flow (the vSphere VCM path) to generate zone/failure-domain information dynamically from VCM-provided platform.json, eliminating reliance on hard-coded vSphere zone/pool definitions.

Practically:

• The vSphere VCM config step now derives per-pool zones from platform.json’s failureDomains (when present), using replica-aware selection capped to CONTROL_PLANE_REPLICAS / COMPUTE_NODE_REPLICAS and configured pool sizing via POOL_COUNT (defaulted to 4 in the relevant chains/workflows).
• It renders YAML zone blocks (via jq) for the control-plane (CP_ZONES_BLOCK) and compute (W_ZONES_BLOCK) and injects them into the generated install-config platform sections (including the compact size variant), inserting the zone blocks after diskSizeGB: 120.
• The legacy vSphere “zonal” step/chain and step documentation are marked deprecated and are no longer used by the updated ipi-conf-vsphere-zones chain; migration guidance is added to use the VCM-based flow (e.g., via the vsphere-elastic cluster profile).
• Related vSphere E2E zonal workflows and the e2e-vsphere-ovn-zones job configuration are updated to set POOL_COUNT, ensuring zone generation follows the updated pool-count-driven behavior.