Add module setup troubleshooting notes

[dashitongzhi]

Summary

• Add troubleshooting steps for missing module dependencies, external commands, and API keys
• Include commands to confirm BBOT version/path, reinstall managed dependencies, inspect module help, and test one affected module
• Document where to place API keys and how to pass them with -c for a single run

Testing

• Ran a markdown sanity check to confirm the new section exists and fenced code blocks are balanced

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[liquidsec]

This is probably a good thing to have. However, we are currently in the process of updating the docs for 3.0 release so we will need to let those land first.