Add guide for using conda-auth in Docker containers

[travishathaway]

What is the idea?

Many automation users run conda in their Docker containers. We would like to target a guide to these user which walks through how to use this plugin there.

Why is this needed?

Make the project more user friendly and give conda users a starting point for integrating this plugin into their own environment.

What should happen?

Write a guide that will appear as a separate page. Here's a title that could work, "Using with Docker". Make sure to nest this page underneath the "User Guide" section. This guide should appear in the sidebar menu for the documentation website.

Additional Context

No response