URLs need to be rethought

From announcing new RAs, the URL is kinda clunky:

`https://architecture.cncf.io/architectures/colopl/`

Needs to be better for social. Are we expecting to host other things on the subdomain?

- `https://architecture.cncf.io/colopl/agones/#`
- `https://architecture.cncf.io/colopl/something else?`

I am also constantly mixing up architectures vs. the singular word. architectures.c.i doesn't work but I type it all the time. So we should just reserve those names and forward to whatever the correct DNS trick is.

The issue names no files, tests, or entry points. Start by reviewing the current architecture.cncf.io URL and DNS setup, then compare the proposed URL forms and define the redirect behavior; done means a documented, agreed URL structure with the required redirects in place.

Written by the indexing model from the issue text.