[DOC] - Add tutorial on adding a batch of users to keycloak

[kcpevey]

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

Once you set up a new Nebari instance, you generally want to add a bunch of users and no one wants to do that by hand. This is particularly true for intermittent deployments for tutorials and workshops.

@iameskild has a gist with some code that converts a csv to a json format that can be imported into keycloak. We should turn that into a doc page (and long term make it part of the cli).

Gist: https://gist.github.com/iameskild/07b7578b16ba9d389659e086cc021274
Initial discussion/request: https://github.com/orgs/nebari-dev/discussions/1749

Steps to Resolve this Issue

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