Adding data from openmc.org

[shimwell]

As discussed briefly in #14 it would be great to have some of the h5 files that are currently found on openmc.org

To do this then there are a few stages, another base repository to template that would take a different approach to the existing template repository.

The new template would download from https://openmc.org/official-data-libraries/ then extract the contents and self commit to the repo using a GitHub action.