[TR] Provide Entity Model for groups of road users

An unambiguous definition for the Domain Model should be provided for "Traffic" and possible sub-ordinate classes. Initial sources for definitions shall include:

• OpenXOntology
• OpenSCENARIO 1.0
• OSI
• OpenSCENARIO 2.0 Concept Project

Further input can be gathered from other standards and of course directly from OpenSCENARIO 2.0 developers. The discussion shall be documented on this ticket. The assignee of this ticket is responsible to ensure that discussion will be held and to drive the discussion towards a definition that is ready for integration in the standard document.