Support flexStart capacity with non-queued provisioning

[jesus-orozco]

The current capacity flags automatically append --enable-queued-provisioning when selecting flex-start. This should be an optional argument available to the end user for enabling nodepool creation with either flex-start provisioning option (queued vs non-queued).

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 7 days.

[jamOne-]

What was the use-case exactly? Does #631 and #686 solve the issue?