separate builtin models from contributed models in the marketplace

[pkienzle]

Users are going to the marketplace to find a model that isn't already available in sasview. Don't make them scan through models that are already available to do so.

The fix could be as simple as tagging each builtin model with [builtin] so that sort puts them at the end of the list for the category.

[butlerpd]

The tag does exist but is not visible until one clicks on a model where it shows up under Details as In Library. It does also show up in the model list as author since builtin show up with SasView as the author vs an actual author. What is needed is to add a sort option on each column of the model list to allow sorting by name.

This however is not a SasView repo item but a marketplace issue so moving it.