First pass at export task
Cleaned up some logging
Added a sleep to the polling for export status
Changed logic for selecting unsanitized users to "Is Admin". Cleaned up messages
Merge branch 'anurse-19-exportdbtask' into dev

Conflicts:
	Source/NuGetGallery.Operations/DeploymentEnvironment.cs
	Source/NuGetGallery.Operations/NuGetGallery.Operations.csproj
	Source/NuGetGallery.Operations/Tasks/BackupDatabaseTask.cs
	Source/NuGetGallery.Operations/Tasks/ExportDatabaseTask.cs
	Source/NuGetGallery.Operations/Tasks/SanitizeDatabaseTask.cs
	Source/NuGetGallery.Operations/packages.config