Acceptance criteria:

When adding / editing a machine pool of an HCP cluster, UI should allow 500 max nodes.

This work is behind a feature flag - "max-compute-nodes-500"

To scale to max 500 nodes, cluster must have a minimal OCP version to support it. In case the cluster in not at the minimal version, UI should limit scaling to max of 90 nodes.

Minimal versions to allow more then 90 nodes: 4.15.15, 4.14.28.