Linktree page

[fguisso]

Usage:

---
layout: linktree
links:
  - "Extra links": "https://example.com"

---

This layout show all your social links from your .Params.Author.links and show extra links from the actual page.

There is my Live Demo, but it's not equal to this PR, I have customized with more code.

Here is a live demo using de blowfish exampleSite

[nunocoracao]

Thanks for this @fguisso I'll be rejecting this PR though.
Something like this would need an issue an some thoughts. Don't intend to add more code to maintain at this stage unless some users want it. Also, the design doesn't really align with the rest of the theme.