Implement ARIA Feed role.

[geoffrey-eisenbarth]

I will say that this is by no means "production ready" but I wanted to start some discussion on it. A few things:

1. The hotkeys values that contain + don't work, I think there's a bug in the hotkeys util.
2. I'm not sure how to get feed to reinitialize after e.g. htmx loads more <articles> in the role="feed".
3. I need to add documentation/examples, but wanted to get input on the code first.

Thanks!