more info on `matrixinfo` and update `redcap2reproschema`

[yibeichan]

our latest redcap2reproschema ignored Matrix Group Name and Matrix Ranking?, I guess we skipped them during some iterations. we need to add them back with matrixInfo

• should be added to our Activity Model as well (related to [wip] Adding InputType enum reproschema#540)
• need one PR for updating redcap2reproschema.py
• might need another PR for UI to handle this

[djarecka]

I believe that was the decision we made, that this will not be used, but perhaps that was only temporarily. Is this feature explained anywhere?

I'm not sure how this is related to InputType