Add deploy_version reader to QA environment

What does this MR do?

Part of gitlab-com/gl-infra/delivery#1179 (closed)

Add the ability to read DEPLOY_VERSION passed in from gitlab-qa

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content