* Added content to data structure readme.md
Added basic understanding of data structures with a free-read content
* Update readme.md
* Update content/roadmaps/106-javascript/content/104-javascript-data-structures/readme.md
* Update content/roadmaps/106-javascript/content/104-javascript-data-structures/readme.md
Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>