DomainResult.Mvc: Add extension to convert IDomainResult to IResult

[AKlaus]

Currently, DomainResult.Mvc package converts IDomainResult and IDomainResult<T> to IActionResult and ActionResult<T>.

.NET 6 added IResult for producing common HTTP responses (see announcement).

Hence, DomainResult.Mvc package has to provide extensions to convert

• IDomainResult to IResult;
• IDomainResult<T> with (IDomainResult, T) to IResult<T>.

NOTE: IResult is independent from IActionResult and is meant to be used in the minimal APIs:

app.MapPut("/todos/{id}", async (TodoDbContext db, int id, Todo todo) =>
{
    if (id != todo.Id)
        return Results.BadRequest();

    if (!await db.Todos.AnyAsync(x => x.Id == id))
        return Results.NotFound();

    db.Update(todo);
    await db.SaveChangesAsync();

    return Results.Ok();
});