Add additional TFM to eliminate explicit dependencies

**Is your feature request related to a problem? Please describe.**
Currently the library is targeting only net standard 2.0 which is resulting in a large dependency graph which could be reduced,

**Describe the solution you'd like**
Adding an additional TFM (ie net 6 & 8) as well as placing conditions on the dependencies which are natively available via the framework ie `System.Diagnostic.DiagnosticSource`.

**Describe alternatives you've considered**
Accept the dependencies.

**Additional context**
Azure team are already working on this for the monolithic sdk repo.