Add timezone autocorrection for timezone differences

We can add a heuristic to detect timezone offsets of senders using the perceived difference between the current UTC time of the server and the parsed time from the log message.

Check for different time of 30mins intervals, the shortest possible timezone difference.
If the time falls into approximate timezone diff slots, we can assume the sender sends in a different timezone.
Store this fact alongside the original message, to be able to alert on it and also to be able to display the correct timestamp.