add a barebones privacy policy, will likely need to expand it if the service gets more usage

lib/entendu_web/controllers/page_controller.ex

@@ -10,4 +10,9 @@ defmodule EntenduWeb.PageController do
     |> clear_session()
     |> render("index.html")
   end
+
+  def privacy(conn, _params) do
+    conn
+    |> render("privacy_policy.html")
+  end
 end