[Federation] Cleanup unused code in service controller

[shashidharatd]

Post merging the PR #41258, lot of unused code is left behind in federation service controller. These changes were segregated to this PR, so that the original PR was small and manageable.

Release note:

NONE

cc @kubernetes/sig-federation-pr-reviews

[k8s-reviewable]

This change is 

[shashidharatd]

@k8s-bot unit test this

[nikhiljindal]

/lgtm
/approve

[shashidharatd]

@k8s-bot unit test this

[csbell]

I'd rather not have us revert this. Until we have pre-merge testing, please invoke the bot (even though yes it looks like routine cleanup :-).
@k8s-bot pull-kubernetes-federation-e2e-gce test this

[shashidharatd]

@csbell, pre-merge tests for federation have already passed. https://k8s-gubernator.appspot.com/pr/44960

[csbell]

Apologies, had not seen it.
/lgtm

[k8s-github-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: csbell, nikhiljindal, shashidharatd

Needs approval from an approver in each of these OWNERS Files:

• federation/pkg/federation-controller/OWNERS [csbell,nikhiljindal]

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[k8s-github-robot]

Automatic merge from submit-queue (batch tested with PRs 43395, 44960)

[shashidharatd]

Thanks @csbell, @nikhiljindal