Raise warning about columns in TSV that have not been annotated

[alyssadai]

This could include:

• Ratio of # columns with Neurobagel annotations / total # columns in TSV
• A list of names of the unannotated columns (maybe gets verbose for very wide TSVs?)
• A link to the annotation tool and encourage folks to annotate other columns OR open an issue about variables that can't be annotated

[github-actions]

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