Film spreadsheet integration

[johnbeech]

Doing a complete rewrite!

• ✅ Use github actions and PR flow to manage change
• ✅ Focus on new v4 google API using theoephraim/node-google-spreadsheet at v3.1.15 with enforced authentication
• ✅ Add a CI test for end-to-end authentication flow using github secrets
• ✅ Update README
• ✅ Use async await pattern instead of promises in examples