* add spark internal book

* change slideshare like to forked repository

* Update books/free-programming-books-th.md
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

* update TOC

* change TOC title to group of content
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

* trigger linter

* remove typo

* Ordering TOC

* re-arrange book section

* more specific document to Thai version
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>