refactor magic links in Header file, incl. routes

src/lib/components/Header.svelte

@@ -1,6 +1,8 @@
 <script lang="ts">
 	import Chevron from '$lib/icons/Chevron-right.svelte';
 
+	import { ROUTE_NAMES } from '../../routes';
+
 	export let data;
 </script>
 
@@ -11,7 +13,7 @@
 			aria-label="Global"
 		>
 			<div class="flex w-48">
-				<a href="/" class="-m-1.5 p-1.5 w-10">
+				<a href="{ROUTE_NAMES.ROOT}" class="-m-1.5 p-1.5 w-10">
 					<span class="sr-only">Tatort Niedersachen</span>
 					<img class="h-8 w-auto" src="/Landeswappen_NI.svg" alt="Landeswappen Niedersachsen" />
 				</a>
@@ -19,7 +21,7 @@
 			<h1 class="text-3xl text-slate-400 font-bold">Tatort</h1>
 			<div class="lg:flex lg:justify-end w-48">
 				{#if data.user}
-					<form method="POST" action="/anmeldung?/logout">
+					<form method="POST" action="{ROUTE_NAMES.ANMELDUNG_LOGOUT}">
 						<input type="hidden" />
 						<button type="submit" class="text-sm font-semibold leading-6 text-gray-900"
 							><span