NONMEM was placed in wrong block

it belongs to EstimationStepType as optional choice with
ObjectiveDataSet
trialStructure.xsd removed

this file was not used for trial design, but rather trialDesign.xsd only
changes in modelingSteps

name related: NONMEMdataSetType
and 'EstimationStepType' extend by
<xs:element name="NONMEMdataSet" type="msteps:NONMEMdataSetType"…