Revert a translated page back to an alias page

[phildexter]

Mozilla reported that sometimes they need to convert a page they have translated by mistake back to an Alias page.

We will implement this as an option from the bottom drop up menu on a translated page Convert to alias page

Then take the user to a confirmation step "Are you sure?"

We would leave any page revisions and translations in the database in case the user wants to turn it back into a translated page again.