Separate add-ons into report columns

For GiveCampus reporting.

The standard custom-report registry exposes Add-Ons as a summary column rather than dynamically generating a column for each item. Export and transform a working copy into per-item columns when the summary contains the needed quantities, or request an authorized item-level extract. Activities and add-ons are different structures; changing a label does not make activity attendance reporting available for an add-on.