Eliminate STJ dependency for net 6

[thompson-tomo]

Is your feature request related to a problem? Please describe.
I want to minimise dependencies in my project by utilising framework dependencies wherever possible

Describe the solution you'd like
I want the package to not have an explicit dependency on System.Text.Json as it can be provided by the framework when targeting net 6. The same for an other system provided dependency.

Describe alternatives you've considered
Accept the additional dependency

Additional context

• System.Text.Json is only included for net standard 2.0/2.1 & net framework 472 Ark.Tools Ark.Tools.SystemTextJson
• System.Diagnostics.DiagnosticSource is only included for net standard 2.0/2.1 & net framework 472 and not the net 6 package for Ark.Tools.SystemTextJson and Ark.Tools.NLog
• Microsoft.Bcl.AsyncInterfaces is only included for net standard 2.0/2.1 & net framework 472 and not the net 6 package for Ark.Tools.Core