[Bugfix] Partially revert custom codec selection (#279)

* Removed and re-added codec preference columns

* Removed custom codec work from download options builder

* Updated settings UI

* Made codec preferences non-optional fields

lib/pinchflat_web/controllers/settings/setting_html.ex

@@ -1,8 +1,6 @@
 defmodule PinchflatWeb.Settings.SettingHTML do
   use PinchflatWeb, :html
 
-  alias Pinchflat.Downloading.CodecParser
-
   embed_templates "setting_html/*"
 
   @doc """