PM-209: limit snapshots

Context

• Project README link: https://gitlab.cern.ch/mpe-ms/devops/ansible/java-server/blob/PM-209-limit-snapshots/README.md
• Task details: https://its.cern.ch/jira/browse/PM-209

What was done

• A new set of cleaning tasks was written, which remove older snaphosts after the deployed server has started.
• All snapshots above a (configurable) threshold are deleted

QA

• Ansible, so no formal QA.

Review objectives

• assessment of code functionality
• assessment of code quality
• knowledge sharing