Add submode for standard Python logging module

[xmacex]

The standard Python logging module produces something like this

WARNING:root:Watch out!

It is a Sisyphean task to try to include submodes for different logging solutions and situations (as hinted in the README), but maybe some popular ones would be nice little contributions to this nice Emacs package?

[doublep]

It would be nice if you created another pull request with the required changes for this issue. I hope I will not forget about it this time.