Added GrassCoverErosionOutwardsHydraulicLocationEntity and the Create method. Updated PersistenceRegistry to support two different types of entities for the same data model type. Related to Issue [WTI-846] git-svn-id: https://repos.deltares.nl/repos/WettelijkToetsInstrumentarium/trunk@5423 5a3db67b-de53-47b5-99c8-a1c30a6650e2