Implement GetConverterInfo(src, dst) method #62

It is extremely complicated to implement dynamic converters using the C# library. It is impossible to integrate a dynamic form/workflow, etc., without writing a ton of extra code and extra dependencies to parse the OpenAPI schema manually.

I suggest implementing a strongly typed model for the converter, something like:

public class Converter
{
    public string Title { get; set; }
    public string Summary { get; set; }
    public string AcceptsFormats { get; set; } // to build a form with accepts=".docx,.dot.,.doc" attribute
    public bool AcceptsMultiple { get; set; }
    public Dictionary<string, string> Parameters {get; set;}
    ...
}

And a method GetConverterInfo(src, dst), that parses the OpenAPI schema under the hood and returns a strongly typed model with all the required metadata about the converter, which allows building dynamic converters effortlessly.