Implement ADAL logging callback for NetCore

[MiYanni]

Currently, there is a bug in the version of ADAL (3.19.2) we are using for NetCore.
AzureAD/azure-activedirectory-library-for-dotnet#1028

This version is resolved directly from Common.Authentication.Abstractions.Netcore via Microsoft.ClientRuntime.Azure.Authentication which uses ADAL 3.19.2. For now, to avoid this issue, we have disabled logging for ADAL via LoggerCallbackHandler.UseDefaultLogging = false; set in AzureSessionInitializer.cs in Common.Authentication.Netcore. This is simply a workaround so that logging information isn't written to the console directly.

For us to have proper ADAL logging, we need to implement a callback. Basically, we can add this callback method to the AdalSession and set it via LoggerCallbackHandler.LogCallback. More information can be found here:
https://github.com/AzureAD/azure-activedirectory-library-for-dotnet/wiki/Logging-in-ADAL.Net

We have to do this even if we upgrade to 3.19.4 (current version). The reason is because .NET Core has no default output for logging. You can see that here:
https://github.com/AzureAD/azure-activedirectory-library-for-dotnet/blob/82565905ca0213e7963a275c40382a8560f9d141/adal/src/Microsoft.IdentityModel.Clients.ActiveDirectory/Platforms/netstandard1.1/AdalLogger.cs#L40

Note: We would keep LoggerCallbackHandler.UseDefaultLogging = false; for NetCore since we'd have this callback. Even if they implement a default logger down the line, we want it to use our callback anyway.

[markcowl]

Closing in favor of MSAL update