Add ClearMLLogger.v2

[shadeMe]

Description

This PR refactors commonly reused code into separate functions and adds ClearMLLogger.v2.

v2 changes/adds the following:

• The logger no longer calls the console logger internally. To avail oneself of both, the ChainLogger needs to be used as the main logger.
• log_custom_stats has been added as a new optional parameter, which is a list of regexps. Keys in the info dictionary that match any of these regexps are automatically logged to ClearML.

Types of change

Refactor/New feature

Checklist

• I confirm that I have the right to submit this contribution under the project's MIT license.
• I ran the tests, and all new and existing tests passed.
• My changes don't require a change to the documentation, or if they do, I've added all required information.