Compile the WebUI and response with it if webui is enabled.

frontend/components/NoApi.vue

@@ -0,0 +1,14 @@
+<template>
+  <div class="notification is-warning">
+    <h1 class="title is-5">There is no <em class="is-bold">{{ api_var }}</em> configured.</h1>
+    <p>Please configure the API connection using the button <i class="fa fa-cog"></i> in the top right corner of the
+      page.</p>
+  </div>
+</template>
+
+<script setup>
+import {useStorage} from "@vueuse/core";
+
+const api_url = useStorage('api_url', '')
+const api_var = computed(() => (!api_url.value) ? 'API URL' : 'API token')
+</script>