Export participants to different formats

* CSV
* PDF (requires Python dependency `weasyprint`)
* ODS (requires Python dependency `pyexcel_ods3`)

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

test/service/workers/export_cleaner_worker.ex

@@ -0,0 +1,14 @@
+defmodule Mobilizon.Service.Workers.ExportCleanerWorkerTest do
+  @moduledoc """
+  Test the export cleaner worker
+  """
+
+  alias Mobilizon.Service.Workers.ExportCleanerWorker
+  alias Oban.Job
+
+  use Mobilizon.DataCase
+
+  test "Run clean" do
+    assert :ok == ExportCleanerWorker.perform(%Job{})
+  end
+end