[FEATURE REQUEST]: Use System.Text.Json for Json serialisation

**Is your feature request related to a problem? Please describe.**
Currently this library uses Newtonsoft.Json for Json serialisation in IPC. [System.Text.Json](https://devblogs.microsoft.com/dotnet/try-the-new-system-text-json-apis/) was released recently and is faster and more memory efficient.

**Describe the solution you'd like**
For the Json serialisation to be done with System.Text.Json.

**Describe alternatives you've considered**
-

**Additional context**
I'd be happy to take this on if this seems like a good idea.