Fix EZP-22735: Make {{ path( 'ez_urlalias' ) }} polymorphic

A fix for already existing issue at JIRA: https://jira.ez.no/browse/EZP-22735

Common usecase is to generate an URL to content in Relation field value.
>  (not considering the issue that together with object ID, legacy stored node ID selected in /content/browse, instead of main one as the new stack does)

If that should be re introduced, then we need a native location relation, to avoid all the issues we have had with those extra values on relation-list.