[Bugfix] Properly escape NFO files (#168)

* Properly escaped NFO file contents

* Added an NFO backfill worker

* Added a try-catch to the backfill since I _really_ don't want failures to halt app boot

lib/pinchflat/podcasts/rss_feed_builder.ex

@@ -5,6 +5,8 @@ defmodule Pinchflat.Podcasts.RssFeedBuilder do
 
   @datetime_format "%a, %d %b %Y %H:%M:%S %z"
 
+  import Pinchflat.Utils.XmlUtils, only: [safe: 1]
+
   alias Pinchflat.Utils.DatetimeUtils
   alias Pinchflat.Podcasts.PodcastHelpers
   alias PinchflatWeb.Router.Helpers, as: Routes
@@ -94,14 +96,6 @@ defmodule Pinchflat.Podcasts.RssFeedBuilder do
     """
   end
 
-  defp safe(nil), do: ""
-
-  defp safe(value) do
-    value
-    |> Phoenix.HTML.html_escape()
-    |> Phoenix.HTML.safe_to_string()
-  end
-
   defp generate_self_link(url_base, source) do
     Path.join(url_base, "#{podcast_route(:rss_feed, source.uuid)}.xml")
   end