Tag subsets with a copy of the factor value's characteristics when subsetting

[arteymix]

When looking at a subset (i.e. https://dev.gemma.msl.ubc.ca/expressionExperiment/showExpressionExperimentSubSet.html?id=11403&dimension=8420), the only information regarding the factor value is encoded in the title. The idea would be to also copy some of the characteristics from that factor value as subset annotations.

The characteristics in a FactorValue are statements, which carry a little bit more than a single term. I think it would be sufficient to copy all the categories and subjects.

This is already done when subsetting by cell type for single-cell data.

This might be backfillable in the database by looking at the analysis result sets.