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/router.ex

@@ -61,6 +61,9 @@ defmodule Mobilizon.Web.Router do
     plug(:accepts, ["atom", "ics", "html"])
   end
 
+  pipeline :exports do
+  end
+
   pipeline :browser do
     plug(Plug.Static, at: "/", from: "priv/static")
 
@@ -78,6 +81,11 @@ defmodule Mobilizon.Web.Router do
   pipeline :remote_media do
   end
 
+  scope "/exports", Mobilizon.Web do
+    pipe_through(:browser)
+    get("/:format/:file", ExportController, :export)
+  end
+
   scope "/api" do
     pipe_through(:graphql)