[Spike] - See if vanity imports puts us in an infinite loop

1. Create a vanity import under your own domain name, `marwan.io/mycoolpackage`
2. Have the vanity import return a meta to an athens server (localhost since we don't have athens up yet) ``
3. Run `GOPROXY=http://localhost:3000 go get marwan.io/mycoolpackage`
4. Proxy will internally call `go mod download` on `marwan.io/mycoolpackage`, which will then redirect `go mod download` to use a mod server, which is the Proxy itself and so we potentially end up in an infinite loop.

Whether we redirect to CDN or not matters, but that depends on the type of storage and whether it's Proxy/Registry.