Add an ansible playbook for RHEL 8 test dependencies

[mrc0mmand]

cc @psss

Fixes #3

[psss]

Thanks for the playbook, Franta. Looks good. I would only suggest to place L2 metadata into a separate branch (or directory) so that the two metadata levels are not mixed. Here's how the rhel-8 branch could look like, including the initial version of the ci.fmf file:

• https://github.com/psss/systemd-tests/tree/rhel-8

What do you think?

[psss]

After discussion with @mrc0mmand I've created a pull request directly in the rhel8 repo:

• WIP: Enable basic smoke test using the L2 metadata systemd-rhel8#11

Please, have a look.