Test to deploy serverless functions to Vercel.com
      - [x] Implement functions in a Serverless functions idiomatic way
      - [x] Typescript
      - [x] Reason about Edge caching strategy (duration, client + edge)
      - [x] Requests validation via YUP
      - [x] Find out about CORS
      - [x] Build : TS => Not needed
      - [x] Protect / from directory listing
      - [x] GCP interop for Cloud SQL
      - [x] Per env config