Detect and convert to subdomain URL's

[dokterbob]

Gateway URL's should be transformed to <root_cid>.ipfs.gatewaydomain instead of using /ipfs/ or /ipns otherwise all IPFS resources share the same security context!

This is a big security concern!

Background: https://consensys.net/diligence/blog/2021/06/ipfs-gateway-security/

[dokterbob]

Ref: ipfs/in-web-browsers#89

[polluterofminds]

I believe this is resolved with this commit: 18b9b1e

Heads up though, this did introduce a bug where full path filenames aren't working (i.e. ipfs/CID/myfile.png). There's a bug open and we'll hopefully have a fix for that soon. #11