Add a check to the datasets page to not display an empty page if there are no datasets

frontend/src/routes/datasets/+page.svelte

@@ -4,11 +4,23 @@
   let { data }: PageProps = $props();
 </script>
 
-<ul>
+<svelte:head>
+  <title>List of datasets</title>
+</svelte:head>
+
+{#if data.datasets.length}
   {#each data.datasets as dataset}
+    <nav>
+      <ul>
         <li>
-      <strong>{dataset.name}</strong><br />
+          <a href="datasets/{dataset.id}"><strong>{dataset.name}</strong></a><br
+          />
           {dataset.description}
         </li>
-  {/each}
       </ul>
+    </nav>
+  {/each}
+{:else}
+  <h1>No datasets yet!</h1>
+  <p>Try adding a dataset through the backend.</p>
+{/if}