Minor consolidation of Environment Variables

[njbrake]

What's changing

This pull request involves several changes to update environment configuration files and improve the setup for local development and testing. The key changes include renaming the environment template file, updating references across the codebase, and modifying environment variable defaults.

Environment Configuration Updates:

• .env.example renamed to .env.template and updated with additional comments and placeholders for various configuration sections. [1] [2]

Makefile Adjustments:

• Updated Makefile to reference the new .env.template file instead of the old .env.example file.
• Added necessary environment variables for backend unit and integration tests in the Makefile.

Documentation Update:

• Updated the reference to the environment file in docs/source/user-guides/inference.md from .env.example to .env.template.

Backend Settings Update:

• Modified lumigator/python/mzai/backend/backend/settings.py to remove default values for S3_BUCKET, RAY_HEAD_NODE_HOST, and RAY_DASHBOARD_PORT, indicating that these should be specified in the .env file.

How to test it

Steps to test the changes:

1. Run make local-up, check to see if .env file variables are correctly loaded.

Additional notes for reviewers

The idea of this PR is that now the environment variable file is only used for overrides, not for regular settings.

I already...

• Tested the changes in a working environment to ensure they work as expected
• Added some tests for any new functionality
• Updated the documentation (both comments in code and product documentation under /docs)
• Checked if a (backend) DB migration step was required and included it if required

[javiermtorres]

LGTM. I'll wait for other opinions before approving, though.
I agree with keeping defaults in a single point, and adding configuration if needed.

[agpituk]

I think this is a great consolidation PR @njbrake ! Just added a minor comment on the Makefile. Also, what do you think about also having the SQLALCHEMY_DATABASE_URL in the .env file instead of the docker-compose.yaml? in order to consolidate things in one place.

[njbrake]

I think this is a great consolidation PR @njbrake ! Just added a minor comment on the Makefile. Also, what do you think about also having the SQLALCHEMY_DATABASE_URL in the .env file instead of the docker-compose.yaml? in order to consolidate things in one place.

@agpituk would it be ok if we push that change off into a future change? Tbh I'm not totally sure how the database setup works yet, and that env var shows up in enough places that I'm not yet confident that I won't accidentally break something when trying to change it 😆 .

[agpituk]

I think this is a great consolidation PR @njbrake ! Just added a minor comment on the Makefile. Also, what do you think about also having the SQLALCHEMY_DATABASE_URL in the .env file instead of the docker-compose.yaml? in order to consolidate things in one place.

@agpituk would it be ok if we push that change off into a future change? Tbh I'm not totally sure how the database setup works yet, and that env var shows up in enough places that I'm not yet confident that I won't accidentally break something when trying to change it 😆 .

definitely! :) I'll open an issue so we don't forget. Thanks @njbrake