Proposal to store capacity ranges or specify a maximum capacity for transport elements

Originally brought up [here](https://forums.buildingsmart.org/t/weightcapacity-in-ifctransportelement-is-a-single-value/2669).

Pset_TransportElementCommon has a property called CapacityWeight.

Cranes, if they are a transport element can either be described as their maximum capacity (e.g. this is a 50T crane), or as a series of capacities at different jib positions.

Option 1: IFC wants to support capacity tables, so add a table property data type.

Option 2: IFC wants to support maximum capacity only, change the docstring to read as such.