As the old way to include tasks is deprecated, replace static include
statements with import_tasks and dynamic ones with include_tasks.
Increaded the required ansible version to 2.5.0 to make sure that
include_tasks and import_tasks is working as expected.
Fixes issue #38
The relative import of the distribution specific vars files requires to use
is not working. {{ role_path }} needs to be used to force the load of the
proper files.
