Logging Changes

[arcinfini]

Resolves #216

• Alters the common logger variable to _log.
• Removed commonly found loggers in cogs.
• Converted non-important info logs to debug.
• Added the ability to assign an environment variable to define the logging level. A default level of debug is used.

Reviewers Note

Take a look at the logic for the configurable logging level in the birdbot.py newly renamed logging_context contextmanager.