Future issue: Modify integration workflow to incorporate additional covariates for harmony

[allyhawkins]

In working on adding in the harmony process, I realized that if we want to actually use the harmony covariates in practice we will need to make a modification to add in any information that we would want to use as a covariate to the colData of the merged object. My initial instinct is that we should use the patient id/ participant id as a covariate to start when integrating with harmony. To do that we will need to add that column to the object somehow. I haven't thought about this too much other than that information isn't currently being passed through any of the processes and is also not in the objects so we will have to think about how to incorporate it if we want to use it. I just wanted to file this issue so I don't forget.