added train/validation split for InfiMNIST
added train/validation split for InfiMNIST

bssrdf/deeppy,appapantula/deeppy,deepesch/deeppy,LWHTarena/deeppy,andersbll/deeppy_experimental,mqyqlx/deeppy,ilo10/deeppy,lre/deeppy,manashmndl/deeppy,nishantsbi/deeppy,MohammedWasim/deeppy,hendrikTpl/deeppy,rakeshkurakula/deeppy,rajat1994/deeppy,redreamality/deeppy,3manuek/deeppy,mhdella/deeppy,andersbll/deeppy