Add a parking space object

[schmidtlorenz]

Describe the feature

In OpenDrive parking spaces are defined as objects. Such an object is missing in OSI.

Describe the solution you would like

There needs to be an object representing parking spaces in OSI which aligns with the description in OpenDrive.
One way would be as Stationary Object. However, Stationary Objects might be falsely identified as hazard or road blockage.
Hence, RoadMarking would be more fitting. This might also allow to partially implement access rules for parking spaces via the traffic sign description in RoadMarking. The remaining problem is to find a way to express the upcoming (OpenDrive 1.8) feature of a "parking space ID" (as seen in ,e.g., a car park).

An alternative would be to add a new class "ParkingSpace", that could be structured according to the implementation in OpenDrive.

Describe the backwards compatibility

I see no backwards compatibility issues.

[thomassedlmayer]

Harmonization WG 2023/03/01: Use cases are not clear yet. Could you give some more information on the use case? Is this a requirement for sensor modeling/traffic participant modeling/AD function? What information on the parking spaces is required? Also, what about moving parking spaces? @tbleher @schmidtlorenz
From harmonization point of view we did not see the need to just adapt whatever there is in OpenDrive without further reasons. In terms of physical lanes it would also be interesting how that would be handled in the ISO23150.