Replace findInventoryEventPlan.ftl with form widgets

While troubleshooting production run requirements created from the Mrp I evaluated findInventoryEventPlan.ftl for conversion to a form widget which I generally do for any FTL file I encounter since I find the widgets much easier to interpret. Other than the the ERROR mrpEventType record not being combined with the INITIAL_QOH line, I was able to reproduce the FTL with a form widget.