feat: add graceful shutdown for healthy-check http server.

[fengruotj]

The same as this pr: volcano-sh/volcano#4285.

StartHealthz() provides health checks for volcano-controller, volcano-admission, and volcano-scheduler.

Regarding the stop channel returned from signal handling: if multiple handlers are waiting on different channels, only one of them will be triggered. Therefore, we must use signals.SetupSignalContext() to handle signals, as it will close the signal channel, allowing multiple handlers to be triggered simultaneously.

[volcano-sh-bot]

Welcome @fengruotj!

It looks like this is your first PR to volcano-sh/apis.

Thank you, and welcome to Volcano. 😃

[fengruotj]

Why i got the following message:
You're not authorized to push to this branch. Visit https://docs.github.com/repositories/configuring-branches-and-merges-in-your-repository/managing-protected-branches/about-protected-branches for more information.

[fengruotj]

/assign @hwdef

[fengruotj]

PTAL, makes code strong & elegance together .

[fengruotj]

/assign @k82cn

[volcano-sh-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: hzxuzhonghu
Once this PR has been reviewed and has the lgtm label, please ask for approval from k82cn. For more information see the Kubernetes Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[hzxuzhonghu]

/lgtm