feat: paginate member list, add create member button

frontend/src/lib/components/ErrorAlert.svelte

@@ -0,0 +1,15 @@
+<script lang="ts">
+  import type { APIError } from "$lib/api/entities";
+  import { Alert } from "sveltestrap";
+
+  export let error: APIError;
+</script>
+
+<Alert color="danger" fade={false}>
+  <h4 class="alert-heading">An error occurred</h4>
+  <b>{error.code}:</b>
+  {error.message}
+  {#if error.details}
+    ({error.details})
+  {/if}
+</Alert>