[feature request] Move to System.Text.Json to support AOT

Hi,

AOT is one of the biggest features in last .NET versions:
https://learn.microsoft.com/en-us/dotnet/core/deploying/native-aot/?tabs=net7%2Cwindows
It would be great if Microsoft would update its library ecosystem to support own features.
Newtonsoft.JSON will not support AOT:
https://github.com/JamesNK/Newtonsoft.Json/issues/2732

There are also several extra benefits:
1.) Less dependencies
- smaller size
- less maintenance incl. security issues

2.) System.Text.Json has better performance

Thanks!

Start by locating the SDK's Newtonsoft.Json usage and the serialization entry points across the repository, then check how existing tests cover those paths. Done means the relevant serialization uses System.Text.Json and the SDK remains covered by tests while supporting AOT without the existing JSON dependency.

Written by the indexing model from the issue text.