Backport getting-started command/log-path fixes to 3.27

[claude]

Requested by Ole Herman · Slack thread

Backport to the 3.27 release branch of #3717 (merged on master).

This cherry-picks 4 code-sample corrections in getting-started documentation. Docs-only changes to make copy-pasted commands and paths correct.

Before / After

• A trust-key example used the wrong SSH host variable, targeting the client instead of the hub — now points at the hub.
• The install-log path pointed at the non-existent /var/logs/ — now the correct /var/log/.
• A bootstrap example used the outdated cfagent bootstrap invocation — now the current cf-agent --bootstrap.

Per-file fixes

• secure-bootstrap.markdown: ssh "$CLIENT_SSH" → ssh "$HUB_SSH".
• general-installation/_index.markdown: /var/logs/cfengine-install.log → /var/log/cfengine-install.log.
• general-installation/installation-enterprise.markdown: /var/logs/cfengine-install.log → /var/log/cfengine-install.log.
• general-installation/installation-enterprise-free-aws-rhel.markdown: cfagent bootstrap → cf-agent --bootstrap (x2).

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Generated by Claude Code

[claude]

Superseded by #3723 — recreated with git cherry-pick -x for backport provenance.