feat: new login experience (#2139)

* feat: multiple auth instances

* fix: auth setup + strategy initialization

* feat: admin auth - add strategy

* feat: redirect on login - group setting

* feat: oauth2 generic - props definitions

* feat: new login UI (wip)

* feat: new login UI (wip)

* feat: admin security login settings

* feat: tabset editor indicators + print view improvements

* fix: code styling

client/components/admin.vue

@@ -129,7 +129,7 @@
             v-list-item-avatar(size='24', tile): v-icon mdi-heart-outline
             v-list-item-title {{ $t('admin:contribute.title') }}
 
-    v-content(:class='$vuetify.theme.dark ? "grey darken-5" : "grey lighten-5"')
+    v-main(:class='$vuetify.theme.dark ? "grey darken-5" : "grey lighten-5"')
       transition(name='admin-router')
         router-view