Feat: Added testimonials in home page

[nagalakshmi08]

Related Issue

Fixes issue #403

Description

Added testimonials in home page, which is responsive and also looks good in both light theme and dark theme.

Type of PR

• [ ] Bug fix
• [x] Feature enhancement
• [ ] Documentation update
• [ ] Other (specify): _______________

Screenshots / videos (if applicable)

https://github.com/CSEdgeOfficial/learn.csedge.courses/assets/121669832/613a92cd-7b5a-4af0-b025-c70451c95df4

Mobile view:

Checklist:

• [x] I have performed a self-review of my code
• [x] I have read and followed the Contribution Guidelines.
• [x] I have tested the changes thoroughly before submitting this pull request.
• [x] I have provided relevant issue numbers, screenshots, and videos after making the changes.
• [x] I have commented my code, particularly in hard-to-understand areas.

Additional context:

Please check it and let me know if changes to be made, Thank you!