Support multi-volcano-scheduler without using selectors in the helm chart (at least) too

[hajnalmt]

What is the problem you're trying to solve

Volcano has a feature:
https://github.com/volcano-sh/volcano/blob/master/docs/design/deploy-multi-volcano-schedulers-without-using-selector.md
But it's not supported in the helm chart yet. In this case we need to deploy the scheduler as a Statefulset not as a Deployment.
https://github.com/volcano-sh/volcano/blob/master/installer/helm/chart/volcano/templates/scheduler.yaml

I think SCHEDULER_NUM should be retrieved from the replicas value (but shall be overrideable too I think).

Describe the solution you'd like

Ability to deploy the scheduler via a Statefulset with helm and use multi-volcano-scheduler feature.

Additional context

The introduction happened in this PR:
#1795

[hajnalmt]

/good-first-issue

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[hajnalmt]

/area deploy

[pinkfloyd-eminem]

/assign