update docker configuration

[lpmi-13]

Description

This commit updates the docker configuration for the project in the following ways:

• moves the ARG lower down in the 2 Dockerfiles to take advantage of layer caching if the image is rebuilt with a different ARG value (the layers above it don't need to be rebuilt).
• removes unnecessary mkdir statements, since WORKDIR runs mkdir under the hood (https://docs.docker.com/reference/dockerfile/#workdir)
• binds the compose stack to the loopback interface instead of all interfaces, which means if running on an unsecured subnet (eg, coffee shop wifi) no other hosts will be able to send traffic to the container.

🤝 Attestations

• My proposed changes don't update any code and are only updates to the container configuration

[vidplace7]

Can you actually break this out as a variable (Add in .env.example) and default to 127.0.0.1?

Beyond that nitpick this PR looks good ❤️ thanks for the submission!

[lpmi-13]

Yep, can do 🫡

I was actually wondering, given the nature of this project, if there are some times you'd like it to run on one host and be reachable from another (or maybe there's some other reason I'm missing about why you'd want it bound to 0.0.0.0/0...CI maybe?).

[lpmi-13]

I also added the .env file to the .gitignore, but if it's intentional that it's not in there, I can easily take it out and add a comment about why we don't want it.