avocado.core: Add output module

This module is a rough idea of a facility library that
helps writing avocado entry points. The ideas there
definitely need some polishing.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
avocado: Add sysinfo and logs to tests

Create logs directory, with tests structure, logs and
sysinfo directories. We still have a long way towards
the minimum requirements we want for the first sprint,
but we're getting closer.

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