docs

This test is using the galaxy_importer from ansible project. The
configuration file galaxy-importer.cfg is copied from linux-system-roles

    https://github.com/linux-system-roles/auto-maintenance/blob/master/\
    lsr_role2collection/galaxy-importer.cfg

The tests script has extra code to parse the output of the importer to
highlight errors and to exit with a proper error code.

The test can be used locally also with "sh tests/sanity/sanity.sh"

New files:
- .github/workflows/ansible-test.yml
- tests/sanity/galaxy-importer.cfg
- tests/sanity/sanity.sh