[DOCS] Add multiple READMEs in their respective folders

### Description

Currently, we have a readme where it explains the use of the directory builder.
However, that guide is outdated, and we do not have guides for the other script(s).

I suggest we add a `README.md` inside their respective folders explaining what it does, how it works, etc..
Let me know your thoughts about this. Thank you. 🙂
