implemented storing of bookmarks

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

frontend/src/Components/Menu.svelte

@@ -41,6 +41,7 @@ onMount(fetchModules);
     <a href="#" onclick={() => go('/project')}>{t('projects')}</a>
     <a href="#" onclick={() => go('/task')}>{t('tasks')}</a>
     <a href="#" onclick={() => go('/document')}>{t('documents')}</a>
+    <a href="#" onclick={() => go('/bookmark')}>{t('bookmarks')}</a>
     <a href="#" onclick={() => go('/notes')}>{t('notes')}</a>
     <a href="https://svelte.dev/tutorial/svelte/state" target="_blank">{t('tutorial')}</a>
     {#each modules as module,i}<a href={module.url}>{module.name}</a>{/each}