Create CI workflow that checks README.docify.md's are in sync with README.mds

[iulianbarbu]

#5954 will introduce a README.md generated from a README.docify.md. We used docify::compile_markdown! inside the lib.rs of the staging-chain-spec-builder crate.

We must search for README.docify.md in the repo, and run cargo build --features generate-readme in the dir of the file (assuming it is related to a crate). If the git diff shows some output for the README.md, then the file update wasn't pushed on the branch, and the workflow should fail.

[virajbhartiya]

Can I work on this?

[iulianbarbu]

Hey @virajbhartiya ! Thanks for the interest and sure, you can look into it. Will assign this to you in the meantime.