internal/http/template: add plausible.io script tag

fixes https://gitlab.inf.unibz.it/lter/browser/-/issues/135

Author: palmamartin

internal/http/templates/base.tmpl

@@ -26,6 +26,7 @@
 		<script src="/assets/third_party/jquery/jquery-ui.min.js"></script>
 		<script src="/assets/third_party/bootstrap/js/bootstrap.min.js"></script>
 		<script src="/assets/third_party/cookies-eu-banner/js/cookies-eu-banner.js"></script>
+		<script defer data-domain="browser.lter.eurac.edu" src="https://plausible.io/js/plausible.js"></script>
 		<link rel="icon" type="image/png" sizes="32x32" href="/assets/favicon-32x32.png">
   		<link rel="icon" type="image/png" sizes="16x16" href="/assets/favicon-16x16.png">
   		<link rel="apple-touch-icon" href="/assets/favicon-196x196.png">