Add a validation  that systemd-container package is installed before starting adoption.

If the package wasn't installed for OSP17, all workloads will be killed during EDPM adoption.

DoD proposal after discussions:

• Implement a role in edpm-ansible to perform validation that systemd-container package is installed
• Add a validation step that runs the validation role into the Adoption docs and tests (a separate EDPM Deployment with just a single service for the validation). This comes before the point of no return from rollback perspective, last thing before we start adoption of the data plane nodes.

Acceptance criteria:

• The epdm-ansible validation role has been properly added. 
• The validation role has been added in the adoption test-suite CI before EDPM Adoption.
• The documented procedure is verified with standalone.