Remove abstract flag from RequiredObject.

...agent/provider/GenericAgentConfigurationItemProvider.java

...gent/provider/GenericAgentItemProviderAdapterFactory.java

...s.descartes.prisma.agent.generic/model/genericagent.ecore

...risma/agent/generic/genericagent/GenericAgentFactory.java

...tes/prisma/agent/generic/genericagent/RequiredObject.java

...nt/generic/genericagent/impl/GenericAgentFactoryImpl.java

...nt/generic/genericagent/impl/GenericAgentPackageImpl.java

...a/agent/generic/genericagent/impl/RequiredObjectImpl.java