Docker update: Build script entirely in container, better handling of config options through docker env vars

[mgrimace]

Docker changes:

Build script within the container

• Changes to Dockerfile: The script should now be built entirely within the docker container when the docker image is built. As in, no need to install node.js locally or build the script once before switching to docker.
• Same install instructions - docker requires the source code, and docker compose up -d --build each time config options are changed.

Better handling of config options provided as environmental variables in compose.yaml

• Note: Changes to Load.ts! Since many of the config options are integrated into the script when it is built, I had to make changes to the Load.ts to optionally pass in config values when they are specified by the user as environmental variables in their compose file.
• When building, the script should read/prioritize docker env var values, and if not specified, fall back to the original config.json values.
• I did some testing on my own system to ensure that the changes to Load.ts didn't break the script for non-docker user. On my system it works either as a base script and as docker, but please review the code changes for Load.ts.
• Ideally, this means a docker user can specify all their config options directly in their compose.yaml.

As always, thank you for your work on this, and feel free to edit, change, ignore anything I've done here.

[mgrimace]

Pausing this PR, need to test something on my end