feat(social-menu): adjustments to social links, adding linked in

[mndonx]

Summary

This PR makes small adjustments to the social links:

• Adjusts extend formatting
• Adds LinkedIn icon
• Renames parent directory "social menu" (instead of "social")

Explain the motivation for making this change. What existing problem does the pull request solve?

Part of initiative to solidify component markup.

How to review this PR

• [x] Visit Social Menu component in Emulsify.
• [ ] Ensure that the markup is clean and easily repurposed.

[github-actions[bot]]

:tada: This PR is included in version 1.11.0 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket: