Centralize hardcoded and repeated URLs

[aniket866]

🐛 Describe the bug

1. Redundant Code: The codebase repeats the same external URLs for social and project links in multiple places instead of defining them once.

2. Important URLs like the GitHub repo and the AOSSIE homepage are hardcoded as strings again and again.

3. This repetition occurs across at least four different component files: Navbar.js, Hero.js, About.js, and Footer.js.

4. Hard to Maintain: If a URL ever changes, you have to find and fix every single instance of it manually.

5. Risk of Errors: It's easy to miss one instance when updating, leading to broken or inconsistent links on the site..

PROPOSED SOLUTION:

• Create a "Truth" File: Make a new single file, like src/constants/urls.js, to hold all external links.

• Define Variables: Inside that file, save each URL string to a clear variable name (e.g., GITHUB_URL).

• Use Everywhere: Import those variables into your components and use them instead of the hardcoded URL strings.

@M4dhav wants to work on this Please assign

[M4dhav]

I don't think this is needed at this stage, maybe something for #56