[Enhancement] Add Media Center support for videos uploaded on the same day (#221)

* Added upload date index field to media_items

* Added incrementing index for upload dates

* Added media item upload date index to download option builder

* Added new season_episode_index_from_date to UI; updated parser

* Improve support for channels

* Hopefully fixed flakey test

priv/repo/migrations/20240502161955_add_upload_date_index_to_media_items.exs

@@ -0,0 +1,11 @@
+defmodule Pinchflat.Repo.Migrations.AddUploadDateIndexToMediaItems do
+  use Ecto.Migration
+
+  def change do
+    alter table(:media_items) do
+      add :upload_date_index, :integer, null: false, default: 0
+    end
+
+    create index("media_items", [:upload_date])
+  end
+end