feat: Add golangci-lint

[mateusoliveira43]

Add more linting checks to project with golangci-lint.

.golangci.yaml is similar to the one proposed at vmware-tanzu/velero#7194

Test

Run golangci-lint with new make lint and make lint-fix commands.

TODO

All go files changes where done through make lint-fix command. There are still a lot of issues to be resolved in the code.

golangci-lint comes with newer versions of kubebuilder, if #1250 is accepted, merge this one first and add golangci-lint to operator-sdk version update docs.

[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: mateusoliveira43
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[weshayutin]

/hold

[weshayutin]

let's have a little demo / socialization of what the lint rules are first.

[openshift-ci]

@mateusoliveira43: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/4.14-e2e-test-kubevirt-aws	561b736	link	true	/test 4.14-e2e-test-kubevirt-aws

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[openshift-merge-robot]

PR needs rebase.

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[mateusoliveira43]

closing in favor of #1337