Add showing and modifying user name (#306)

Make sure to use the user name field everywhere

Add showing and modifying user name

Co-authored-by: kolaente <k@knt.li>
Reviewed-on: https://kolaente.dev/vikunja/frontend/pulls/306
Co-Authored-By: konrad <konrad@kola-entertainments.de>
Co-Committed-By: konrad <konrad@kola-entertainments.de>

src/views/Home.vue

@@ -1,6 +1,6 @@
 <template>
 	<div class="content has-text-centered">
-		<h2>Hi {{ userInfo.username }}!</h2>
+		<h2>Hi {{ userInfo.name !== '' ? userInfo.name : userInfo.username }}!</h2>
 		<template v-if="!hasTasks">
 			<p>Click on a list or namespace on the left to get started.</p>
 			<router-link