avocado.core.output: Refactor console colors code

Rename Bcolors to TerminalColors, and add new methods
that will already yield common strings ready for exibition:

1 - A colored header string
2 - Colored PASS, FAIL, ERROR, SKIP strings

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
avocado.linux.software_manager: Fix logging calls
avocado.cli.app: Fix PEP8 problem
logging: Remove linux and utils loggers

Leave only avocado.app and avocado.test loggers, the
former for console output, and the later, for test and
job logs.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>