Rethink the interfaces around `IJsonWriter`

[corranrogue9]

IJsonWriter, IJsonWriterFactory, IJsonStreamWriter should all be reworked with Utf8JsonWriter and CborWriter in mind

[corranrogue9]

This is a possible CBOR implementation to investigate: https://github.com/dahomey-technologies/Dahomey.Cbor

[corranrogue9]

This is mostly around removing the use of textwriters.