Need to log EasyAuth enablement details from Host

[mathewc]

Currently the Functions Host enables Easy Auth middleware for non-Windows SKUs based on an environment variable WEBSITE_AUTH_ENABLED configured by the platform based on site auth config (code here).

However, the host doesn't emit any logs indicating whether this auth is enabled, making investigations difficult. We should have HostEasyAuthOptions implement IOptionsFormatter which is our standard way of ensuring the host logs critical config on startup. We can add additional logs as well as needed, the goal being to be able to easily tell whether a host has EasyAuth enabled and configured correctly.

This came up in a CRI investigation recently. Without this, we have to go dump environment for a running instance.