Multiple sinks per logging group

[igor-egorov]

The feature request is to have the ability to set several sinks for the same logging targets. It would be great when Kagome is able to duplicate all the console output to the file too. Moreover, enabling this will let us put reduced logs to the console and detailed (e.g. with more traces) to the file. Thus the file log would be a superset for console logs, making it easier to navigate through the file in case of any error happened and was visible from console logs.

[xDimon]

Will be resolved when #20 be merged