[FEATURE REQUEST] Passwordless SSH communication for postgres user between DB nodes

[to-bar]

Is your feature request related to a problem? Please describe.
Manual setup of SSH keys is required in order to be able to run repmgr standby switchover command.

Automation of the SSH setup would simplify testing of repmgr.

Describe the solution you'd like
Generate and exchange SSH keys between PostgreSQL nodes when replication is enabled.

Describe alternatives you've considered
n/a

Additional context
We already have similar solution in core\src\epicli\data\common\ansible\playbooks\roles\backup\tasks\common\download_via_rsync.yml

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DoD checklist

• Changelog
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• COMPONENTS.md
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• Schema
  • updated
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• Backport tasks
  • created
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• Documentation
  • added
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• Feature has automated tests
• Automated tests passed (QA pipelines)
  • apply
  • upgrade
  • backup/restore
• Idempotency tested
• All conversations in PR resolved