Added backend api of contact form

[Sawan-Kushwah]

**Title: Backend for contact form

**Issue No.: #221

Close #221

Untitled.design.4.mp4

Followed proper folder structure !!
MONGO DB compass SS , data submitted successfully on database !!

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 created a helpful and easy-to-understand README.md if it's a new page/tech stack.
• [ X] I have gone through the contributing.md file before contributing.

Additional context (Mandatory):

Are you contributing under any Open-source programme?

• [X ] I'm a GSSOC-EXT contributor
• [ X] I'm a HACKTOBERFEST contributor

[netlify]

👷 Deploy request for bitbox-in accepted.

Name	Link
🔨 Latest commit	8823737
🔍 Latest deploy log	https://app.netlify.com/sites/bitbox-in/deploys/671c8db84b8ac10008ea08f0

[github-actions]

Thank you for submitting your pull request! 🙌 We'll review it as soon as possible. In the meantime, please ensure that your changes align with our chaotic CONTRIBUTING.md. If there are any specific instructions or feedback regarding your PR, we'll provide them here. Thanks again for your contribution! 😊

[Sawan-Kushwah]

@Anuj3553 this PR doesn't get merge is there something wrong with it or its under review ?

[github-actions]

🎉🎉 Thank you for your contribution! Your PR #258 has been merged! 🎉🎉

[Anuj3553]

Well done @Sawan-Kushwah