installer script: support node and new zc config files

[jeffreyc-splunk]

See the doc changes for details.

I tested these changes locally since the installer script only installs the instrumentation packages that have been released to artifactory. After the changes from #3791 are released, I will update the CI tests for the new package.

[github-actions]

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✅ (atoulme)[https://github.com/atoulme]
❌ @jeffreyc-splunk
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