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/components/sharing/userTeam.vue

@@ -46,7 +46,7 @@
 				<tbody>
 				<tr :key="s.id" v-for="s in sharables">
 					<template v-if="shareType === 'user'">
-						<td>{{ s.username }}</td>
+						<td>{{ s.getDisplayName() }}</td>
 						<td>
 							<template v-if="s.id === userInfo.id">
 								<b class="is-success">You</b>