EZP-23478: added redirection form fields in content/edit.tpl

> See [EZP-23478](https://jira.ez.no/browse/EZP-23478)
> See ezsystems/ezdemo#38

Adds `content/edit_redirection.tpl`, included from `content/edit.tpl`. Allows one to pass redirect uris & discard uris from the website toolbar.