Rework the handling of 1:M relationships by the Faces scaffold

The generated Faces scaffold for 1:M relationships does not handle certain usability aspects.

For example, a new row is automatically added by default when displaying a 1:M relationship upon create. However, unless the add button is clicked, the contents of the row are not added to the underlying managed bean. If the add button is not clicked, the contents of the row are not treated as a new item to be added. This is very confusing.

Also, if bean validation is performed on the entities (in the rows of the 1:M relationship), and if it fails, then the contents need to be corrected, even though they may not be persisted in the database. Again, this is confusing behavior.

Additionally, deletion of entities from the collection (1-side of the association) seems to be broken (FORGE-974).