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>

lib/web/views/export_view.ex

@@ -0,0 +1,17 @@
+defmodule Mobilizon.Web.ExportView do
+  use Mobilizon.Web, :view
+
+  alias Mobilizon.Service.Address
+  alias Mobilizon.Service.DateTime, as: DateTimeRenderer
+  import Mobilizon.Web.Gettext
+
+  defdelegate datetime_to_string(datetime, locale \\ "en", format \\ :medium),
+    to: DateTimeRenderer
+
+  defdelegate datetime_to_time_string(datetime, locale \\ "en", format \\ :short),
+    to: DateTimeRenderer
+
+  defdelegate datetime_tz_convert(datetime, timezone), to: DateTimeRenderer
+  defdelegate datetime_relative(datetime, locale \\ "en"), to: DateTimeRenderer
+  defdelegate render_address(address), to: Address
+end