AuditLog no longer uses initialization module

AuditLog no longer uses initialization module.

Needed services need to be registered in using application by calling AddAuditLog() in ConfigureServices method of startup.

And to actually enable the logging call UseAuditLog() in Configure method of startup.

NuGet package available from Optimizely NuGet feed:

• https://nuget.optimizely.com/
• https://api.nuget.optimizely.com/v3/index.json