Allow to join an open group

Also:

* Refactor interacting with a remote event so that you can interact with
  a remote group as well
* Add a setting for group admins to pick between an open and invite-only
  group
* Fix new groups without posts/todos/resources/events/conversations URL
  set
* Repair local groups that haven't got their
  posts/todos/resources/events/conversations URL set
* Add a scheduled job to refresh remote groups every hour
* Add a user setting to pick when to receive notifications when there's
  new members to approve (will be used when this feature is available)
* Fix pagination for members

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

js/src/components/Event/EventCard.vue

@@ -73,10 +73,11 @@
 </template>
 
 <script lang="ts">
-import { IEvent, IEventCardOptions, ParticipantRole } from "@/types/event.model";
+import { IEvent, IEventCardOptions } from "@/types/event.model";
 import { Component, Prop, Vue } from "vue-property-decorator";
 import DateCalendarIcon from "@/components/Event/DateCalendarIcon.vue";
 import { Actor, Person } from "@/types/actor";
+import { ParticipantRole } from "../../types/participant.model";
 import RouteName from "../../router/name";
 
 @Component({