new api_endpoint store + Config UI

ref #9

src/App.svelte

@@ -1,5 +1,5 @@
 <script>
-  console.log("app started with base url " + config.endpoint);
+  import { apikey, api_endpoint, lang, page } from "./store.js";
   import { addMessages, init } from "svelte-i18n";
   import en from "./locales/en.json";
   import de from "./locales/de.json";
@@ -11,13 +11,13 @@
   import Scanner from "./Scanner.svelte";
   import Login from "./Login.svelte";
   import Settings from "./Settings.svelte";
-  import { apikey, lang, page } from "./store.js";
   $: is_configured = $apikey && $apikey !== "null" && $apikey !== "";
   $: settings_open = $page === "settings";
   init({
     fallbackLocale: "en-US",
     initialLocale: $lang,
   });
+  console.log("app started with base url " + $api_endpoint);
 </script>
 
 {#if settings_open && is_configured}