CDDL sync

[thomas-fossati]

Things to consider:

1. corim.digest won't be available in time, and even if it were, since it's CBOR-only, we'd need to add the JSON counterpart...
2. the EAT types (JC, and sw-version-type) will hopefully become available automatically via the cddl(1) tool once 9711 is published.

[hannestschofenig]

Relying on the constantly evolving list of new CDDL features, which are not yet implemented in validation tools or code generators, is obviously risky.

I cannot really give a good recommendation on what to do there because there are also benefits in using these features.