Updated Google Shopping sources

Google Shopping sources now use the token-based system, replacing the product_id workflow. google_shopping_search (with render enabled) now provides a token required for google_shopping_product requests.

Additionally, google_shopping_pricing is no longer supported as a standalone source. To extract pricing data, use the google_shopping_product source.

Finally, google_shopping_product can now expand the "More Shops" panel to access additional listings by submitting the job with render: 'html' (only first expansion is available).