Structured log in HttpLoggingMiddleware

[Kahbazi]

Fixes #33038

[wtgodbe]

This addresses #33038 in practice, but I'm not sure it does in spirit - we're still concatenating the objects to strings in the middleware, so logger implementations still don't have access to the original objects - @davidfowl do we think that's a goal here?

[Tratcher]

HttpRequestLog has the list of individual objects, though I think AddToList needs to be changed from string? to object? as well. What objects aren't strings to begin with?

[wtgodbe]

At least HttpRequest.QueryString is not a string:

aspnetcore/src/Middleware/HttpLogging/src/HttpLoggingMiddleware.cs

Lines 106 to 109 in accd569

	if (options.LoggingFields.HasFlag(HttpLoggingFields.RequestQuery))
	{
	AddToList(list, nameof(request.QueryString), request.QueryString.Value);
	}

[Tratcher]

It's mostly a string 😁. Passing the wrapper object preserves a little context. the same for Path. Anything else?

[wtgodbe]

There are some I'm adding in W3C, but I can handle those after this is in (Cookie, Query)

[davidfowl]

Yes this is fine.