Media downloading indexing options (round 2) (#14)

* Adds options + option builder + metadata parsing for media thumbnails

* Added release-type options to media profile; built option parser for indexing operations

* Added new media_profile options to creation form; made show helper for rendering database items

* Added options for downloading/embedding metadata

* Adds option on sources to not download media (index only)

* reformatted docs

priv/repo/migrations/20240206204740_add_download_media_to_sources.exs

@@ -0,0 +1,9 @@
+defmodule Pinchflat.Repo.Migrations.AddDownloadMediaToSources do
+  use Ecto.Migration
+
+  def change do
+    alter table(:sources) do
+      add :download_media, :boolean, default: true, null: false
+    end
+  end
+end