Allow extension/packages installation via ENVIRNOMENT variables

[ThomDietrich]

💡 Summary

Please provide a way to install additions to this image e.g. via docker compose file.

Previously mentioned at https://community.home-assistant.io/t/weewx-mqtt-and-how-to-import-data/212344/28

Motivation and context

We all know that weewx is only useful in addition with a few extensions for most users.

You have provided these workarounds in your README:

• https://github.com/felddy/weewx-docker?tab=readme-ov-file#installing-weewx-extensions
• https://github.com/felddy/weewx-docker?tab=readme-ov-file#installing-python-packages

It would be a small change to your entrypoint script, but a huge improvement for the end user of your image if this capability was provided via env variables, especially useful inside of a docker compose managed setup.

As an example, here is how Grafana does it: https://grafana.com/docs/grafana/latest/setup-grafana/installation/docker/#install-plugins-in-the-docker-container

Implementation notes

This is probably just a few lines of code :) Happy to discuss and test.

Acceptance criteria

How do we know when this work is done?

• A clean way to use this image in a docker-compose.yaml in conjunction with at least one extension and your home assistant package

[ThomDietrich]

Hello, I've still not switched over to your new version of this image, hoping for this improvement. Any chance you'll look into it any time soon? Cheers!