Update Dockerfile to implement best practices

[AizuddinAkmal]

I've updated the Dockerfile to implement more secure features/configuration
Changes made:

• Using Debian as the base Node image instead of the unofficially supported Alpine image
• Explicitly configure yarn to explicitly only install production dependencies
• Run the container as a non-root user and ensure files are owned by the non-root user
• Inclusion of dumb-init to allow proper handling of signals

References:

• Alpine-based images use resources from unofficial-builds.nodejs.org nodejs/docker-node#1754
• https://github.com/nodejs/docker-node/blob/main/docs/BestPractices.md
• https://snyk.io/blog/10-best-practices-to-containerize-nodejs-web-applications-with-docker/

[Alee14]

Done