RFC7807 - Standardize API error messages

[nabeelio]

Standardize the API error messages according to the Problem Details for HTTP APIs RFC. Don't remove the old error messages since they don't collide.

Fields:

• type - URL describing error (optional?)
• title - Title of the error
• detail - Details
• status - HTTP status code

Example:

HTTP/1.1 404 Not Found
Content-Type: application/problem+json
Content-Language: en

{
  "type": "https://phpvms.net/problems/unknown-airline",
  "title": "Airline not found.",
  "detail": "The request airline was not found",
  "status": 404
}

Links:

• https://tools.ietf.org/html/rfc7807
• https://github.com/Crell/ApiProblem
• https://blog.restcase.com/rest-api-error-handling-problem-details-response/