Feature: Adding a custom scrollbar

[Madhuri36]

Title of Issue and Pull Request must be Same

Issue number

Issue No. : #195

Video/Screenshots (mandatory)

Before:

After:

https://github.com/PranavBarthwal/cosmoXplore/assets/146222028/2b5ca598-e2ee-4530-9b41-b567ce274d27

Checklist:

• [X] I have mentioned the issue number in my Pull Request.
• [X] I have commented my code, particularly in hard-to-understand areas
• [X] I have gone through the contributing.md file before contributing

Additional context:

I have opened a pull request before (#211 ) which was approved by @harshit-sharmaaa but later on had conflicts, so I resolved the conflicts and I am raising a pr again. @PranavBarthwal and @harshit-sharmaaa please review this pr and merge it with main. Thank you.