Jazzy overrides the 'logging' class attributes instead of creating an instance of a logger

[ghiander]

Describe the bug
Jazzy imports logging as a module and changes the formatting of the class attributes instead of creating an instance and changing its attributes - this means that when jazzy is imported by, for example a app (say main.py) that integrates it, Jazzy overrides the global logging attributes, and even the logs of the app will be printed using the formatting adopted by jazzy.

This issue is caused by the command in jazzy/core.py
logging.basicConfig( format="Jazzy %(levelname)s: [%(asctime)s] %(message)s", level=logging.WARNING, datefmt="%H:%M:%S", )

To Reproduce
Steps to reproduce the behavior:
TODO... This was observed in proprietary code

Expected behavior
Only Jazzy logs should be formatted as Jazzy %(levelname)s: [%(asctime)s] %(message)s. Using an instance instead of the module to log messages out will fix the problem.