slog.HandlerOptions.AddSource is a cool feature, but since we moved the
logger to a separate package it no longer works. It now always shows
source info for the log package, rather than the code that called it.
This change removes it.
Before, we were exposing a Logger as logging.Log. This works, but
results in code calling Logger.Log.Info() which is a little wordy.
Instead, the logger is now kept private and we expose Info, Warn and
Error as public functions that wrap logger.Info, logger.Warn and
logger.Error.
