Add custom sidebars to be displayed on Spanish language version of the homepage

[MirandaEcho]

Developer Comment: query param to watch for is ?lang=es, allow users to manage subscriptions.

[benlk]

Do we need to make separate widget areas for this, or is it sufficient to use the control that determines which languages a widget is shown under? https://wpml.org/documentation/getting-started-guide/translating-widgets/displaying-different-widgets-for-different-languages/

[benlk]

Homepage widgets have been translated, and I've duplicated the tips form to provide a Spanish version of the form.