feat: read Node version from .nvmrc

[phillip-kil]

Issue / feature description

This PR enables the CI to read the Node version from the .nvmrc file, so we have a deterministic environment in all pipelines and match the locally used version.

Changes

Read .nvmrc in CI workflows instead of hardcoding the Node version in multiple places.

Checklist

• Rebased to the last commit of the target branch (or merged)
• Code self-reviewed
• Code self-tested
• Tests updated (if needed)
• All tests are passing locally

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