Find all markdown files that are not referenced in SUMMARY.md

[nikivdev]

Need to write a tool for it. So I can clean these files up or link to them if needed.

[yemreak]

You can use my own script to create SUMMARY.md file automatically https://github.com/yedhrab/YGitBookEntegration

[nikivdev]

Thanks. I just need to run a check if all files are covered. As I need to impose my own structure on ordering of files.