Migrate Guardian to the new web3.storage API

[anvabr]

Problem description

Web3.storage announced it would be sunsetting after January 9, 2024 w3name, a hosted IPFS service that allowed users to make mutable references to content on IPFS. They subsequently reversed that decision, i.e. w3name will continue to be supported beyond January 9, 2024.

However this is a 'legacy' approach, which will eventually have to change to a new natively web3 and performant mutability solution that uses web3.storage new UCAN protocol stack. For business continuity, Guardian should ensure timely adoption of the new approach (and/or consider other options).

Requirements

• Adopt new web3.storage API/protocol for Guardian-to-IPFS interactions.
• Ensure backward compatibility with policies and artifacts that have been deployed using the current ('old') naming methods.

Definition of done

• New functionality is implemented as described above
• Documentation is updated accordintly

Acceptance criteria

• Guardian uses new IPFS access method provided by web3.storage
• No user-observable changes to the workflow of policies. (changes in the naming/urls are ok)
• Guardian is backward-compatible with the w3name system, policies and artifacts created then are accepted and processed by Guardian as before

Also consider #1430