Enhance EditMOM3 with nested repeats

Created by: GVogeler

Charter descriptions can have entries which consits of structured data to be edited with a set of visualxml elements (e.g. the witness list (witListPar) which consists of several witnesses with the same structure as currently the description of the original). Jochen says that it is in general possible, maybe cfr https://github.com/xrxplusplus/xpp can help.