Allow for Public/ReadOnly interaction with DWNs

[LiranCohen]

Currently to interact with DWNs through the API you need to first create an Agent + DID, even when attempting to interact with public information.

We'd like to expose a way to query/read/subscribe to records from a remote DWN as an unauthenticated user. As well as Query for protocols as an unauthenticated user.

This will require creating ReadOnly versions of the Record and Protocol classes as well as creating a class similar to DwnApi that only handles the read-only versions of these calls in a friendly way.