Added social media icons in header

[ankurg22]

Please read and understand everything below Do not delete any text other than where you are instructed.

Students: If one of them is applicable to you. Please check it.

Check by changing each [ ] to [x] Please take note of the whitespace as it matters.

• [x] Read and understood (see CONTRIBUTING.md)
• [x] Included a Preview link and screenshot showing after and before the changes.
• [ ] Images are 240 x 240 [w x h].
• [x] Included a description of change below.
• [x] Squashed the commits.

Changes done in this Pull Request

• Social medias like Facebook, Twitter, Github, Youtube are added in the top right corner of the header.
• https://ankurg22.github.io/gci17.fossasia.org/
• Closes #961

[ankurg22]

@abishekvashok @rupav Done. Please review again :blush:

[ankurg22]

@parths007 Please review now.

[rupav]

Good work @ankurg22

[gabru-md]

@rupav please usee Squash and Commit. This avoids an additional merge commit in the logs. :+1: I've already told this to you. But please make sure about this

[rupav]

got it .