Add more NETFramework-compatible APIs for HttpException

[Maples7]

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Add more NETFramework-compatible APIs for HttpException
As the HttpException class in .NET Framework has more actors and public methods, raising this PR to fill the gap.

No issue has been created yet, but open to abandoning this if it doesn't make sense for this adapter.

[dnfadmin]

All CLA requirements met.

[Maples7]

Trying to add some UTs for this.
UTs Added.