move File info / Download button to top of metadata display

[seanaery]

This is probably needed for index & show views. The MEDIA_TYPE field should be the first field displayed in the metadata section so the Download link isn't buried. Presently, when you are on a component's show page or see the component in a search result, the Download link is buried in the middle of the metadata section.

E.g., move these lines:
config.add_index_field Ddr::Index::Fields::MEDIA_TYPE.to_s, helper_method: 'file_info', label: 'File'
config.add_show_field Ddr::Index::Fields::MEDIA_TYPE.to_s, helper_method: 'file_info', label: 'File'

Ultimately, we might want to separate the download button from the media type metadata field for even greater prominence (at least for show view), but moving to the top of that section would be an incremental improvement.