Edits to the Faces page template used in scaffolding should not be overwritten blindly

The Faces scaffold provider overwrites the pageTemplate.xhtml file on every scaffold execution. This results in any changes made by users being lost on invocation. It would be better to detect any modifications and allow users to retain them. In a way, this depends on the ability to allow users to accept or reject changes made to files in a transactional manner.

But we may also want to reconsider this feature of using a Faces template in the generated scaffold, and do away with this.