Node 18 + Manifest Tweak

[cmoesel]

This PR contains a few changes:

• Removes node_modules from change control
• Uses Node 18 by default
• Updates manifest script to not assume a specific folder name
• Updates manifest script to console log a summary of manifests

To test:

• npm install then npm run build
• Note the summary and note that only difference is timestamp
• Add some new examples and remove some old examples
• npm run build again
• Note the differences highlighted in the summary and confirm index.json differences in diff

[cmoesel]

Closed due to GitHub's insistence on running old GitHub Action. Will open a new PR.