did:web:web3.storage should resolve to a did document that we can use to rotate keys

[gobengo]

Motivation

• use did:web for the services so we can rotate keys without having to redo delegations #182
• Use same did across access / upload API services #183

Work

• make a library like @w3protocol/well-known-identifiers in w3protocol that exports the primary capabilityDelegation public key #235
• have @web3-storage/website serve a did doc at /.well-known/did.json and use the key from @w3protocol/well-known-keys
  • maybe use cf pages funtions https://developers.cloudflare.com/pages/platform/functions/routing/

Test

• this should resolve the did doc: https://dev.uniresolver.io/#did:web:web3.storage

[gobengo]

Just spoke with @Gozala . We don't need the publicly-resolving did:web immediately because a lot of the times our validators are going to have a custom did resolver that resolves the did sync against a fixture instead of actually resolving async over the public web.

So for now I am just going to do the subpart of this I just split out into #235

[gobengo]

it resolves! https://dev.uniresolver.io/#did:web:web3.storage