Ability to set alternate content links leading to same page in different language

[Grzegorz Śliwiński]

Page might have different slug (not onky the language prefix might differ).

There should be possibility to create a collection of urls for given route leading to same destination, but in different language.

Preferably, all these links should be injected into document's head with

<link rel="alternate" hreflang="<locale>" type="text/html" href="<translated_uri>"/>