A couple ValueObjectVisitor classes haven't been mapped to services, as they're part of the REST/Client namespace.

Commit @d39b764e can be taken as an example, and even cherry-picked in the pull-request's branch.

Note that an extra commit, https://github.com/ezsystems/ezpublish-kernel/commit/0be433c5f4febbc0dd15f1205faa66736c965f16, is currently required to avoid a scope error. I'm investigating a separate fix for it. In the meanwhile, the commit can also be cherry-picked.