Add Hotjar.com integration

Resolves #148

etc/db-config.yaml

@@ -443,6 +443,11 @@
             default_value: ""
             public: false
             description: The tracking ID for Google Analytics.
+        -   name: hotjar_tracking_id
+            type: string
+            default_value: ""
+            public: false
+            description: The tracking ID for Hotjar.
         -   name: discord_invite_url
             type: string
             default_value: ""

webapp/src/Twig/TwigExtension.php

@@ -162,6 +162,9 @@ public function getGlobals(): array
             'google_analytics_tracking_id'  =>
                 $this->tokenStorage->getToken() && $this->authorizationChecker->isGranted('ROLE_ADMIN') ?
                     '' : $this->config->get('google_analytics_tracking_id'),
+            'hotjar_tracking_id'            =>
+                $this->tokenStorage->getToken() && $this->authorizationChecker->isGranted('ROLE_ADMIN') ?
+                    '' : $this->config->get('hotjar_tracking_id'),
             'discord_invite_url'            => $this->config->get('discord_invite_url'),
         ];
     }

webapp/templates/base.html.twig

@@ -38,6 +38,20 @@
             gtag('config', '{{ google_analytics_tracking_id }}');
         </script>
     {% endif %}
+
+    {% if hotjar_tracking_id is not empty %}
+        <!-- Hotjar Tracking -->
+        <script>
+            (function(h,o,t,j,a,r){
+                h.hj=h.hj||function(){(h.hj.q=h.hj.q||[]).push(arguments)};
+                h._hjSettings={hjid:{{ hotjar_tracking_id }},hjsv:6};
+                a=o.getElementsByTagName('head')[0];
+                r=o.createElement('script');r.async=1;
+                r.src=t+h._hjSettings.hjid+j+h._hjSettings.hjsv;
+                a.appendChild(r);
+            })(window,document,'https://static.hotjar.com/c/hotjar-','.js?sv=');
+        </script>
+    {% endif %}
 </head>
 <body{% if static is defined and static %} class="static"{% endif%}>
 {% block menu %}{% endblock %}