Add analytics collection with Plausible.io

Author: mancellin

docs/source/_templates/layout.html

@@ -0,0 +1,5 @@
+{% extends "!layout.html" %}
+{% block extrahead %}
+    <script defer data-domain="eurobios-mews-labs.github.io/palma" src="https://plausible.io/js/script.js"></script>
+    {{super}}
+{% endblock %}