INodeExecutionData for nodes that wish to enter a form element repetition context during their execution.
 Each form field may be repeated and may have multiple sets of values for each repetition, see e.g.
 
IFormDataAdapter.getIDynContainerMap() and 
IFormContainerMetaData.getIdList(). Within such a context,
 references to 
repeated form fields do not resolve to all values of the form field, but
 only to the values at the indicated repetition index. Useful e.g. for loops that iterate over the repetition of a
 form element.