Audit and update creation and manipulation of errors in the orchestrator and evaluator

Job To Be Done

• When I am calling a function, the errors I receive back from the API are consistent with each other, and as useful as possible, so I can diagnose what is wrong with my call and what I can do to fix it.
• When I am developing a function implementation, whether writing a composition or via 'native' code, I am able to simply, intuitively, and consistently communicate invalid usage to my users through ZErrors, so they can successfully use my implementation.

Acceptance criteria

A normal user…

• … should receive a simplified, specific error for each validation issue, rather than a nested tree of related errors for each - not fixed here; belongs to T301494
• … should always receive the most specific error possible from the orchestrator with trace-ability - covered partly by this work, partly by T301494 , partly by T321235
• … should never receive a generic error from the orchestrator or evaluator
• … should never receive an error from the orchestrator or evaluator with a hard-coded English-only error string (except when it's an error caught from library code, in which case the string is captured as Z500K1)

An implementation writer…

• … should be able to raise an error with a single, simple function call from a composition which is presented to the end user as a ZError - not fixed here; belongs to T305557
• … should be able to raise an error from native code via the normal code-native mechanism which is presented to the end user as a ZError - not fixed here; belongs to T321116

Completion checklist

Functionality:

• The solution meets the expected acceptance criteria described above
• All the child tasks are closed
• The issue has been peer reviewed
• The issue has been merged

Engineering:

• There are existing and passing unit/integration tests effectively testing its success and its failure
• All new classes/methods are covered by unit tests

Documentation

• All new functions/methods are annotated
• Related documentation in MediaWiki extension pages or Abstract Wikipedia pages in meta should be updated with the related changes