Migrate from dlls to nuget

[ar7z1]

Remove Newtonsoft.Json.dll and NLog.dll from repository, add latest corresponding NuGet packages and enable NuGet package restore.
All files in .nuget directory generated by my VisualStudio.

[jstenhouse]

Thanks @ar7z1 for the PR! We have a few things in flight right now that will affect this NuGet PR. We'll update this PR once they land. Thanks!

[ar7z1]

ОК. :-)

[CLAassistant]

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