Use open source Drain3 log-template mining project to monitor for network outages

What this post added

Introduced Drain3, an open-source log-template mining project, as a solution for monitoring network outages in IBM Cloud data centers. Detailed the refactoring of Drain to Python 3, added streaming support with a new `add_log_message()` function, implemented resilient state persistence using Kafka, and incorporated masking prior to de-templating. Explained how log templates can be transformed into time-series data for anomaly detection to identify incidents.