lint: enable all standard linters on project-infra

[dhiller]

Is your feature request related to a problem? Please describe:
As a follow up to #3822 we want to enable the golangci-lint rules that have been disabled in the PR #3825 that integrated the linter but disabled the default linters: https://github.com/dhiller/project-infra/blob/22defd18943880ba3aa05fa11bfeb7203c545774/.golangci.yaml#L6-L14

Describe the solution you'd like:

Goals/Linters to enable:

• staticcheck
• unused
• ineffassign
• govet
• gosimple
• errcheck
• gocyclo with setting: min-complexity: 10 (default is 30)
• remove all //nolint directives

Describe alternatives you've considered:

Additional context:

[dhiller]

/kind cleanup
/wg code-quality
/help

[kubevirt-bot]

@dhiller:
This request has been marked as needing help from a contributor.

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In response to this:

/kind cleanup
/wg code-quality
/help

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