Proposed Initiative - Client Authentication

[justinwb]

As discussed in the panel meeting on 7/13, an initiative for this panel is proposed to design and document the mechanism through which clients are authenticated as part of the Solid-OIDC protocol specification.

This initiative should be sure to work in conjunction with the authorization panel and interoperability panel, who will have a number of applicable and dependent use cases.

[elf-pavlik]

Some relevant notes exist in #25