Revert "Updated solutions to use dotNetRDF from NuGet"

This reverts commit e66ed8386e1686042126e7b780f414528a9149a6.
Revert "Updated NuGet packages to add dotNetRDF dependency"

This reverts commit d39815c2f7d3f9316fa2c412ccf9633bf03e3f32.
Updated dotNetRDF to a newer build
Fixed remaining unit tests issues