Add WebSocket 2023 Channel Type

[acoburn]

This is a first pass at a WebSocket Channel type for 2023. I need to go over all of this will a bit more focus, but it is mostly ready now.

[csarven]

See also:

• https://github.com/solid/notifications/issues/74
• https://github.com/solid/vocab/pull/62
• https://github.com/solid/notifications/issues/98