SO Repository: Adding multi-NS support to remaining non-bulk operations

[pgayvallet]

If most of the bulk APIs of the SOR now support handling either multiple namespaces (e.g find) or to specify the target namespace for each object (e.g bulkCreate), we're lacking the equivalent for most of the non-bulk operation (get or delete for example).

From my understanding, this state is mostly caused by two factors:

• We decided to not alter each individual API until we have a real need to support specifying the namespace the for operation
• Historically, we're not allowing to specify the namespace option of the SOR apis (when spaces is enabled), as this is a reserved option that should currently only be populated by the spaces wrapper, which introduces the question of how we should allow API consumers to specify the namespace when invoking such APIs.

After some discussions in #109197, (where we would have needed to specify a target namespace for delete) one option could be (see #109197 (comment)) to refactor the space wrapper and the base SOR options to rename the current namespace option to currentNamespace. This new property will preserve all the particularities of the old option (considered internal, only populated by the spaces wrapper), while the new-with-old-name namespace option would now be able to be specified by our API consumers.

[elasticmachine]

Pinging @elastic/kibana-security (Team:Security)

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)

[rayafratkina]

We currently have no plans to improve these APIs