support attributes in System.Text.Json.Serialization Namespace

[zijianhuang]

https://learn.microsoft.com/en-us/dotnet/api/system.text.json.serialization

Need to further study vendor recommended ways:
https://www.newtonsoft.com/json/help/html/JsonObjectAttributeOptIn.htm
dotnet/runtime#30180

Need to clarify Microsoft's position.

DataContractAttribute is primarily for WCF and DataContract serializer. WCF service is not a built-in framework in .NET.
Even though DataContractAttribute is universal, not really exclusive to WCF.

[zijianhuang]

wait for response from dotnet/docs#38687