feat(tools/readme_linter): Check for global configuration section

[Hipska]

• Let the CI also enforce the new README section introduced by #12107.
• Update the include section with a more correct link and update this to the example input.
• Add this section also to the netflow input plugin who was missing the section.

Required for all PRs

• [x] Updated associated README.md.
• [ ] Wrote appropriate unit tests.
• [x] Pull request title or commits are in conventional commit format