Resolve "Create Component: rcc-item-list"

Closes #690

Notes

ItemGroup already exists and is fit for the purpose, so I didn't add a new interface.

I struggled with adding the margin in between rcc-list-item-tags, if there is a better way feel free to change it 🙄

Testing

The symptom check selection in the Repose variant lends itself to this: https://localhost:4200/repose-query-run

ItemSelectModalComponent already has Item[] and ItemGroup[] properties, so you can use those as input.