Standardized error 400 messages - API Guidelines

[dsturgell]

Apply API guidelines as per CPR feedback across all relevant repositories.

Next steps:

• [x] Write & review json code
• [x] Update in lang repos
• [x] Update bad.json

Update:

• [ ] C#
• [ ] Typescript
• [ ] Java

Objectives:

• Improve error message response information
• Alignment with Microsoft REST API guidelines
• Improve developer experience
• Reduce impact to performance
• Consistency between C#/Java/TypeScript repos

Opportunities:

• Log warnings for each failed parameter (currently we log only the first)
• Write single/multi-error JSON response for each failed parameter (currently we fail on the first)
• Centralize validation in C# repo, leverage built-in ASP.NET Core model binding/validation
• Write design specification for Helium JSON response - done
• Merge API Guidelines with RFC 7807

Suggested JSON format:

{
    "type": "https://github.com/retaildevcrews/helium/blob/main/docs/ParameterValidation.md#movies",
    "title": "Your request parameters did not validate",
    "status": 400,
    "detail": "One or more invalid parameters were specified.",
    "instance": "/api/movies?year=987&pageSize=999999&genre=1",
    "validationErrors": [
        {
            "code": "InvalidValue",
            "target": "Year",
            "message": "The parameter 'Year' should be between 1874 and 2025."
        },
        {
            "code": "InvalidValue",
            "target": "Genre",
            "message": "The parameter 'Genre' should be between 3 and 20 characters."
        },
        {
            "code": "InvalidValue",
            "target": "PageSize",
            "message": "The parameter 'PageSize' should be between 1 and 1000."
        }
    ]
}

References #493

[aflinchb]

Link to our Parameter Validation spec: https://github.com/retaildevcrews/helium/blob/master/docs/ParameterValidation.md