docs: Enhance Readme.md

what's wrong with the documentation?

I aim to enhance the README file for better organization and readability. @Saurav-Pant sir this is my first issue, I am willing to work on this issue if needed. The readme is well maintained but we can make it better by adding table of content, with gssoc logo we can provide a brief description or link explaining what GSSOC is for newcomers. Standardize font sizes and styles for headings and text to maintain a cohesive look and ensure code blocks are properly formatted with appropriate syntax highlighting. and more

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Record

[X] I have checked the existing issues
[X] I have read the Contributing Guidelines
[X] I agree to follow this project's Code of Conduct
[X] I want to work on this issue

Saurav-Pant / Blood-Donation-Project