Improve member adding and excluding flow

Allow to exclude a member

Send emails to the member when it's excluded

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

lib/mobilizon/resources/resources.ex

@@ -22,7 +22,7 @@ defmodule Mobilizon.Resources do
   def get_resources_for_group(%Actor{id: group_id}, page \\ nil, limit \\ nil) do
     Resource
     |> where(actor_id: ^group_id)
-    |> order_by(desc: :updated_at)
+    |> order_by(desc: :published_at)
     |> preload([r], [:actor, :creator])
     |> Page.build_page(page, limit)
   end