log: Add a log module

Previously the log configuration wasn't consistent. This was due to the
fact that the order of imports determined what class got what logging
configuration. Now a central module handles the configuration and logger
initialization to prevent some bugs.

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=991267
Change-Id: Ica7d81cc9ab73acc4feaab474db3c8ac4258fc42
Signed-off-by: Fabian Deutsch <fabiand@fedoraproject.org>