[DOC] - Add notes on how to integrate/use Loki using the Helm extension logic

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

Logs are usually only available to the administrators who have control of Kubernetes (by kubectl or k9s). This usually leads to problems as the logs do not persist by default, and in case the pod dies before the user gets a glimpse of the errors it's very difficult (sometimes impossible) to retrieve the original logs. As a first step, it would be interesting to include Loki as a tool to aggregate the logs as it goes well with Grafata and has a nice dashboard for exploration and navigating the logs.

Steps to Resolve this Issue

1. Include docs on how to install and use Loki using the helm extension mechanism

Start by locating the existing documentation for the Helm extension mechanism and examples of extensions. Review how Loki is intended to be installed and used for persistent log aggregation and exploration alongside Grafana. Done means the documentation covers installation and basic usage through the Helm extension mechanism.