[Enhancement] Add option for a source to only use cookies when needed (#640)

* Updated model with new attribute

* Update app logic to use new cookie logic

* lots of tests

* Updated UI and renamed attribute

* Updated tests

priv/repo/migrations/20250304185528_add_cookie_behaviour_to_sources.exs

@@ -0,0 +1,18 @@
+defmodule Pinchflat.Repo.Migrations.AddCookieBehaviourToSources do
+  use Ecto.Migration
+
+  def change do
+    alter table(:sources) do
+      add :cookie_behaviour, :string, null: false, default: "disabled"
+    end
+
+    execute(
+      "UPDATE sources SET cookie_behaviour = 'all_operations' WHERE use_cookies = TRUE",
+      "UPDATE sources SET use_cookies = TRUE WHERE cookie_behaviour = 'all_operations'"
+    )
+
+    alter table(:sources) do
+      remove :use_cookies, :boolean, null: false, default: false
+    end
+  end
+end