SystemHandlePassing and various small fixes

* New sample: SystemHandlePassing demonstrates the [system_handle]
  MIDL attribute.
* SystemInsights: Upgrade to Windows Server 1809 and latest NuGet.
* ExplorerDataProvider: Fix redeclaration warning #111
* CrawlScopeCommandLine: Fix copy/pasta bug where we call the wrong method #133
* DeskBand: Fix ODR violation #160 and SetSite method #168