Support redirect host definitions with secondary language branches
As a site owner, I would like to use a redirect HostDefinitionType to redirect secondary domains to the primary domain. This is working in most scenarios.
However, it is not supported when I have one primary domain, and alternative language branches have no separate domains, but are served as "subfolders" on the primary domain.
If, for instance, the primary host definition has "no" as language code, then I can set type to be redirect on a secondary domain, if the language code is the same as the primary host definition.
But if I add a secondary domain, set it to redirect and set language code to, for instance, "en", then I will get a validation error ("Language(s 'en' has redirected hosts but no valid target host." when saving.
I would like this scenario to be supported, so we can support all scenarios with this feature, instead of resorting to URL rewriting middlewares.
