SCE — Unclear scope of identifiers and use of "human"

The documentation for id says "uniquely identify" but not the scope - within a single model, universally?
And for humanID (sic) it's also vague: "the uniqueness of this identifier within a model or relative to some other context."

The intended usage is unclear - calling it "human" does not seem helpful since it's presumably not for human consumption e.g. for display on a diagram?
And "human" is also wrong if the model was generated by a tool, i.e. the "modeler" is not a human.

Without further rules, or a compliance point, interoperability becomes unnecessarily hard.

Remove humanId and make aliasIds a list

The humanId was added to make SCE consistent with KerML (as it was being developed). However, the final beta version of KerML (ptc/2023-06-01) does not include humanId (perhaps because of the inconsistencies identified by this issue). Thus, we can remove it.
Further, we should update the aliasId property - to aliasIds and update its description as necessary.