tools: de-rollup-ify lint-md
The rollup stuff stopped working with the massive remark ecosystem move to ESM. Rather than try to troubleshoot, simplify things by removing rollup. It's a great tool for a lot of uses, but less may be more here.
This does mean checking in a node_modules
directory so that the linter
runs out-of-the-box, like we do for ESLint.