Add leader service

[TaeSooRhee-moreh]

What type of PR is this?

/kind feature
/kind api-change

What this PR does / why we need it

As we can see from the examples, we usually require services for leaders.
Therefore, we can make LeaderService as "[LWS name]-leader" with leaderServicePorts at CR.

Which issue(s) this PR fixes

Fixes #689

Special notes for your reviewer

Does this PR introduce a user-facing change?

NONE

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: TaeSooRhee-moreh
Once this PR has been reviewed and has the lgtm label, please assign edwinhr716 for approval. For more information see the Code Review Process.

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[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: TaeSooRhee-moreh / name: TaeSoo Lee (0e2e095, 1a1039d, 752fa35, 7e2244c, ae70a23, d49b8c2, f7d16f4)

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @TaeSooRhee-moreh. Thanks for your PR.

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[ahg-g]

/hold