podman 1.4 now installs docker man pages. Add handler to remove docker packages to avoid test failure due to this conflict.
Adjust inventory_docker_swarm integration test
Add conditional to cleanup handlers to allow use of the setup_docker role without removing packages at the end of the play. The inventory_docker_swarm integration tests does its own cleanup.
- use include_vars to set appropriate packages and pip packages per distribution and version
- install an older version of Docker CE on RHEL 8 since a dependency is unavailable
- disable warnings on tasks that are ok
- skip tests for CentOS/RHEL 6
