Handle cross-domain destination query parameter with domain source URL rewriting

When adding a query destination parameter to a cross-domain link, we expect to return to the original domain after processing. But, by default, destination parameter are relative only, so it redirects to the targeted domain instead of the original one.

Drupal strips any "destination" parameter that is not internal, so we instead add a custom "destination_domain" parameter that we prepend to the original "destination" parameter after validation (trusted host, no parameter, no fragment).

Current implementation

For now, we only support cross-domain redirects to the current page to avoid any unwanted side-effects.