Adjust golangci-lint linters

[tpantelis]

Added new linters (some commented out if not needed) and removed deprecated linters. Also addressed violations reported by new linters (in separate commits).

Related to submariner-io/enhancements#231

[submariner-bot]

🤖 Created branch: z_pr1700/tpantelis/adj_linters
🚀 Full E2E won't run until the "ready-to-test" label is applied. I will add it automatically once the PR has 2 approvals, or you can add it manually.

[skitt]

I still would like to see “linter” commit descriptions that focus on the improvement to the project rather than the linter that flags the issues — these changes are worth doing because they are an improvement, not to fix a linter violation.

In this case the commit series would look like this:

Remove duplicate words ("on")

This was flagged by dupword.

Use resource.toJSON instead of json.MarshalIndent

This avoids having to check errors everywhere (flagged by errchkjson).

Use integer ranges in for loops

This was flagged by intrange.

Ignore maintidx on purposefully "unmaintainable" functions

Stop using named returns

This is now enforced by nonamedreturns.

Remove unnecessary formatting functions

* string concatenation instead of fmt.Sprintf
* errors.New instead of fmt.Errorf

This is now enforced by perfsprint.

Hopefully that helps illustrate why I think this approach is better. When reviewing the code history later, it’s more immediately apparent what the change is about.