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>

lib/federation/activity_stream/converter/actor.ex

@@ -65,7 +65,8 @@ defmodule Mobilizon.Federation.ActivityStream.Converter.Actor do
       domain: URI.parse(data["id"]).host,
       manually_approves_followers: data["manuallyApprovesFollowers"],
       type: data["type"],
-      visibility: if(Map.get(data, "discoverable", false) == true, do: :public, else: :unlisted)
+      visibility: if(Map.get(data, "discoverable", false) == true, do: :public, else: :unlisted),
+      openness: data["openness"]
     }
   end
 
@@ -98,6 +99,7 @@ defmodule Mobilizon.Federation.ActivityStream.Converter.Actor do
         "sharedInbox" => actor.shared_inbox_url
       },
       "discoverable" => actor.visibility == :public,
+      "openness" => actor.openness,
       "manuallyApprovesFollowers" => actor.manually_approves_followers,
       "publicKey" => %{
         "id" => "#{actor.url}#main-key",

lib/federation/activity_stream/converter/member.ex

@@ -20,7 +20,7 @@ defmodule Mobilizon.Federation.ActivityStream.Converter.Member do
   end
 
   @doc """
-  Convert an event struct to an ActivityStream representation.
+  Convert an member struct to an ActivityStream representation.
   """
   @spec model_to_as(MemberModel.t()) :: map
   def model_to_as(%MemberModel{} = member) do