Draft: SSH: Re-add host key checking

Closes: #494
Superseded-by: !1272 (merged)

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Merge Prerequisites

• Description and title are descriptive
• Code is readable and syntactically correct
• Code is understandable
• Tests added (if needed)
• Docs updated
• Commit messages look good

As a developer: please do not tick these boxes yourself. As a reviewer: please get yourself a hot cold beverage.