New property to relate a Correspondence to corresponding qb:DataSet

[tfrancart]

It is suggested that the matrix of values/ratios attached to a xkos:Correspondence would be captured in a qb:DataSet that can be referred to from the Correspondence.
A new property is suggested to do that:

• xkos:weightedBy
• domain : xkos:Correspondence
• range : qb:DataSet