lint with golangci-lint

[jkhelil]

Changes

golangci-lint aggregate many golang linters to improve code, and help catch real problems.
I didnt enable all the linters but we can do it in multiple steps.

Submitter Checklist

These are the criteria that every PR should meet, please check them off as you
review them:

• Includes tests (if functionality changed/added)
• Includes docs (if user facing)
• Commit messages follow commit message best practices

See the contribution guide for more details.

Reviewer Notes

If API changes are included, additive changes must be approved by at least two OWNERS and backwards incompatible changes must be approved by more than 50% of the OWNERS.

Release Notes

Describe any user facing changes here, or delete this block.

Examples of user facing changes:
- API changes
- Bug fixes
- Any changes in behavior