Add plausible stats tracking, consolidated with jupyter.org stats

I noticed that these docs are served from jupyter.org. This PR is similar to jupyter/jupyter#797. Stats would show up at https://plausible.io/jupyter.org

Author: jasongrout

docs/source/conf.py

@@ -317,3 +317,11 @@ def parse_schema(d, md=[], depth=0, pre=""):
     "architecture": "administrator/architecture",
     "advanced": "administrator/advanced",
 }
+
+def setup(app):
+    # Enable Plausible.io stats for jupyter.org
+    app.add_js_file("https://plausible.io/js/pa-B75UO5--FNXYQSG7GBWkf.js", loading_method="async")
+    app.add_js_file(
+        filename=None,
+        body="window.plausible=window.plausible||function(){(plausible.q=plausible.q||[]).push(arguments)},plausible.init=plausible.init||function(i){plausible.o=i||{}};plausible.init({hashBasedRouting:true})",
+    )