Align the logging approach with Microsoft and Rebus guidelines.

[idoroshenko]

1. Align the logging approach with Microsoft and Rebus guidelines.
2. Provide the ability to access an Error object in the custom ILog implementations.

Reasoning:
We have a request in our project to handle connectivity and network errors differently. That's achievable by implementing a custom ILog logger class and reading the ErrorCode property of the Error class. So it would be useful to have an Error object available also from the Rebus.Kafka originated errors.