Add goargs to CI build

What does this MR do?

Leverages registry.gitlab.com/gitlab-org/ci-cd/runner-tools/runner-linters (built at https://gitlab.com/gitlab-org/ci-cd/runner-tools/runner-linters) to lint with an additional custom linter plugin built from https://gitlab.com/gitlab-org/language-tools/go/linters/goargs.

Based on documentation at https://golangci-lint.run/contributing/new-linters/#how-to-add-a-private-linter-to-golangci-lint

Why was this MR needed?

See #26386 (closed)

What's the best way to test this MR?

Check a failed job: https://gitlab.com/gitlab-org/gitlab-runner/-/jobs/604307879

Output in the MR:

Are there things that the reviewer should be aware of?

• Currently I'm hosting the plugin code at https://gitlab.com/pedropombeiro/goargs. I've opened an access request so that we can move this project to https://gitlab.com/gitlab-org/language-tools/go/linters/goargs.
• I've opened gitlab-com/www-gitlab-com!53809 (merged) to add the new projects to the team's Handbook page, as well as gitlab!35216 (merged) to mention the new location for linter plugins.

What are the relevant issue numbers?

Closes #26386 (closed)