Add bluesky profile support

Adding support for bluesky social. This allows people to set it in their
profile.
Logo is taken from [Wikimedia](https://commons.wikimedia.org/wiki/File:Bluesky_Logo.svg)
and editted via inkscape to match the existing twitter scheme.

I have replaced my twitter link with bluesky as an example.

The change works well with `npm start` locally.

Author: thibmeu

_includes/person_header.njk

@@ -18,6 +18,9 @@
     {% if profile.twitter and profile.status == 'current' %}
     <a href="https://twitter.com/{{ profile.twitter }}" target="_blank" rel="noopener"><img class="twitter" src="/img/twitter.svg" /></a>
     {% endif %}
+    {% if profile.bluesky and profile.status == 'current' %}
+    <a href="https://bsky.app/profile/{{ profile.bluesky }}" target="_blank" rel="noopener"><img class="bluesky" src="/img/bluesky.svg" /></a>
+    {% endif %}
     <!--<img style="height: 1.5rem; position: relative;" src="/img/cloud.svg" alt="orange cloud">-->
     </span>
 </div>

about/people/thibault-meunier.md

@@ -2,7 +2,7 @@
 title: Thibault Meunier
 position: Research Engineer
 status: current
-twitter: thibmeu
+bluesky: thibmeu.com
 blog_author: thibault
 ---