validationResult.ToDictionary() for the Minimal API

[bartoszlenar]

We'll need something like validationResult.ToDictionary(), equivalent of what can be found in FluentValidation https://docs.fluentvalidation.net/en/latest/aspnet.html#minimal-apis.

Feature description

• Probably with some config options (e.g., include full path or just the property name?)
• This is a breaking change as it's modifies public IValidationResult interface