Add --default-load-balancer-scheme command line flag

[phuhung273]

Issue

#3820

Description

• Add --default-load-balancer-scheme command line flag
• For users want to use internet-facing by default
• References: Add --default-target-type flag #2840

Checklist

• Added tests that cover your change (if possible)
  

• Added/modified documentation as required (such as the README.md, or the docs directory)

• Manually tested

Controller abort if input invalid scheme

Controller log

• Made sure the title of the PR is a good description that can go into the release notes

BONUS POINTS checklist: complete for good vibes and maybe prizes?! 🤯

• Backfilled missing tests for code in same general area 🎉
• Refactored something and made the world a better place 🌟

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @phuhung273. Thanks for your PR.

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[shraddhabang]

/ok-to-test

[phuhung273]

@shraddhabang may i know your thought on this PR

[shraddhabang]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: phuhung273, shraddhabang
Once this PR has been reviewed and has the lgtm label, please assign johngmyers for approval. For more information see the Kubernetes Code Review Process.

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[shraddhabang]

@phuhung273 The changes looks good to me. However, we need to review this with our security engineer internally. I will work on that. Will provide you updates when we get that review. Thanks for your contribution.

[phuhung273]

Thank @shraddhabang, im ready for that as discussed in the issue