Radio docs page needs improvement

# Issue summary

There are some improvements to make on the current documentation / example page for the AoRadio component:
- Make the presentation of the demo more consistent with how a group of radio inputs should be presented in a product
- Include a single consistent `name` for all radio inputs in a group per correct usage of the radio input element
- Nest all radio inputs of the group in an enclosing div or proper styling (specifically, vertical spacing provided by the `last-of-type`

## Specifications

- Blaze version number: 3.4
- Browser: Irrelevant
- Device: Irrelevant
- Operating System: Irrelevant