implemented page view for freely available wiki pages

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

frontend/src/routes/wiki/GuestView.svelte

@@ -0,0 +1,51 @@
+<script>
+    import { onMount }       from 'svelte';
+    import { useTinyRouter } from 'svelte-tiny-router';
+    import { api }           from '../../urls.svelte';
+    import { t }             from '../../translations.svelte';
+
+    let { key } = $props();
+
+
+    let error = $state(null);
+    let page = $state(null);
+    let router = useTinyRouter();
+
+    async function loadContent(res){
+        if (res.ok){
+            page  = null;
+            page  = await res.json();
+            error = null;
+            return true;
+        } else {
+            error = await res.text();
+            return false;
+        }
+    }
+
+    async function loadPage(){
+        const url = api(`wiki/page/${key}`);
+        const res = await fetch(url,{credentials:'include'});
+        loadContent(res);
+    }
+
+    function onclick(e){
+        e.preventDefault();
+        let href = e.target.getAttribute('href');
+        if (href) router.navigate(href);
+        return false;
+    }
+
+    $effect(loadPage);
+</script>
+{#if error}
+<span class="error">{error}</span>
+{/if}
+{#if page}
+<div class="wiki page">
+    <h2>{page.title}</h2>
+    <div class="markdown">
+        {@html page.content.rendered}
+    </div>
+</div>
+{/if}