Add identity pickers on event creation & join

Also it now saves current actor in localStorage and initalizes it in
Apollo Cache (just like user stuff). This allows not relying on
loggedPerson query anymore.

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/src/components/Account/Identities.vue

@@ -55,7 +55,7 @@
 
 <script lang="ts">
 import { Component, Prop, Vue } from 'vue-property-decorator';
-import { IDENTITIES, LOGGED_PERSON } from '@/graphql/actor';
+import { IDENTITIES } from '@/graphql/actor';
 import { IPerson, Person } from '@/types/actor';
 
 @Component({