Allow Templates Providers to specify if the resulted page from Template is Hidden or not

Problem: The resulted page copied the Hidden property from the Template.

If the Template is hidden, the resulted page is also hidden, resulting in not being able to search, display that page, unless special Preferences are set. We don't want this behavior for Content/Application Templates resulted pages.

Also the Template is a technical page, so it should be hidden, since they are available from the creation step and the user should not be aware of them.

So we would need to find a mechanism to have the Template be hidden, while the page resulted from the Template be: either visible or hidden.