Cavatica rna seq training updates manifest integration

[cnemarich]

PR Description

Adds additional RNA-seq related training module on how to find CFDE datasets on CFDE Portal and import into a CAVATICA project.

Feedback Requested

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Reviewer Checklist

• [x] spelling and grammar
• [x] successful run of all installation and code chunks
• [x] sufficient explanation and details for the tutorial content
• [x] code syntax and naming convention
• [x] adherence of tutorial format to style guide
• [x] functional links (inter and intra)
• [x] accessible hyperlink text (color blindness test)

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PR Checklist

• [ ] Release label added
• [ ] Category label added
• [ ] Clean build logs
• [ ] Linked related issues
• [ ] Ready for review
• [ ] Ready to merge