I am working with a custom theme in Magento 2.1. I would like site administrators to be able to set the header logo's link via the admin config. This link would then be used in app/design/frontend/vendor/theme/Magento_Theme/templates/html/header/logo.phtml.
By default, I believe it uses
$this->getUrl('') to point to the store's home page. However, I need this to point to an external URL, and the URL depends on which environment the site is running on (i.e. dev, staging, prod).