Rename UI components

[MarcoDeJong]

On the portal homepage you are using the undocumented @redocly/ui components.

To make clear what is a reusable component and what is either markdown or HTML, please prevent using reserved HTML tags for component names.
Please use <Head1>, <Header1> or something else instead of <H1> as this could be a an HTML tag, or HTML in markdown.

[RomanHotsiy]

Oh. That's a nice catch. For some reason, I considered HTML tags user lowercase 🤦...

I'm not sure how to fix that yet as this is going to be a breaking change but I will come up with some plan.

Thanks!