Offer logging to error log for authentication

[michaelryanmcneill]

It would be ideal to offer options for administrators to enable logging. I envision separate options to enable logging for unsuccessful authentication attempts and successful authentication attempts, as well as user creation, manual account merging, automatic account merging, and role updates. This would give administrators additional insight when troubleshooting issues or investigating access attempts.

[michaelryanmcneill]

After testing, it looks to me like all is well. I'm going to update the changelog and close this out.