To ensure passing context in each logger call and thus contribute to log correlation, switch completely to Context Logger across the complete code. Also,
- Remove all the public log methods in log_classic.go; they force stacktrace walk-through for lookup of right logger instance which degrades performance.
- Mark Logger instance as Depreciated; can't remove it yet as it is being used by openonu adapter go version.
- Also introduce a logger instance in log package and use it instead of default logger. It will allow better control of log level of that package.