[Enhancement] Add download rate limiting to app settings (#646)

* Added rate limit column to settings

* Added limit_rate option to command runner

* Added rate limit to settings form

priv/repo/migrations/20250311222451_add_rate_limit_speed_to_settings.exs

@@ -0,0 +1,9 @@
+defmodule Pinchflat.Repo.Migrations.AddRateLimitSpeedToSettings do
+  use Ecto.Migration
+
+  def change do
+    alter table(:settings) do
+      add :download_throughput_limit, :string
+    end
+  end
+end