Reduce Docker image size

[CDDelta]

Currently, the size of the built Docker image is >1GB. It should be possible to reduce this quite significantly with some changes which will make spinning up new gateway instances faster and cheaper.

The size can be reduced in two ways by:

• Making use of multi-stage builds in Docker and only packaging production node_modules in the final image.
• Using a smaller Node image like the Node alpine images.

Dropping the dependency on ts-node brought in by knex would be great as well though I'm not sure how one could do that if migrations need to be ran in the production container.

Multi-stage builds: https://blog.logrocket.com/reduce-docker-image-sizes-using-multi-stage-builds/

Alpine and other Docker images: https://medium.com/swlh/alpine-slim-stretch-buster-jessie-bullseye-bookworm-what-are-the-differences-in-docker-62171ed4531d

[TheLoneRonin]

Love the feedback @CDDelta these are high value adds we definitely want! :D