Incorporate/merge RESTCONF's artifact extension (e.g. rc:yang-data)

[kwatsen]

The head of the on-list thread is here: https://mailarchive.ietf.org/arch/msg/netconf/AWIgm8Hk3nsXLVy3pZvKaNIwedQ

But for some reason it doesn't thread-in some responses:

https://mailarchive.ietf.org/arch/msg/netconf/EpNG1xwFlAsPcSMOTuO0BZ8hIWY https://mailarchive.ietf.org/arch/msg/netconf/BPIuzgFDb5qhLSnNhWMHzURWqYk https://mailarchive.ietf.org/arch/msg/netconf/fsJavJGCkTemu9gLSZoWq005N8I

Note: the last response does seem to have threading working again, so be sure to check out other responses from others.

For those not wanting to read the thread, Juergen wrote, in response to Andy regarding rc:yang-data :

And hopefully some future version of YANG provides proper support for this (and specifications that use the RESTCONF workaround can ideally eventually retire this dependency on RESTCONF in the future).

Martin says:

Yes, I would like to see a new core statement "structure" or something similar, which could be used to define the schema for instances that are not tied to any datastores, operations, or notifications. The semantics of these structures must be defined in the description statement. The core statement "augment" should be extended so that it can be used to augment such structures.

But this requires a new version of YANG.

[schoenw]

I think this is high priority.

[abierman]

Support making structure and augment-structure real keywords in yang-next

• tools must continue to support extensions from RFC 8791