[DOC] - Add information about installing apt packages into user envs using conda-store

[viniciusdc]

Preliminary Checks

• This issue is not a question, feature request, RFC, or anything other than a bug report. Please post those things in GitHub Discussions: https://github.com/nebari-dev/nebari/discussions

Summary

We need to tell users how to install apt packages into their environments, since we will be cleaning out a bit of our Docker images. this will be affected for example https://www.nebari.dev/docs/how-tos/connect-via-ssh/#dangerous-but-useful-information