Add golangci lint

[cpanato]

What type of PR is this?
/kind cleanup
/kind feature

Any specific area of the project related to this PR?
/area build

What this PR does / why we need it:
Add golangci-lint to the project, fix lints and add check lint to the circleci

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

[poiana]

@cpanato: The label(s) area/build cannot be applied, because the repository doesn't have them

In response to this:

What type of PR is this?
/kind cleanup
/kind feature

Any specific area of the project related to this PR?
/area build

What this PR does / why we need it:
Add golangci-lint to the project, fix lints and add check lint to the circleci

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[leogr]

/test all

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Issif

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• OWNERS [Issif]

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[poiana]

LGTM label has been added.

Git tree hash: 8ab61ad20129f787575ca9f9fedef2d5d67c6999