Added attribute in the data model proposal

The criterion can be used in the reply form, and therefore the fulfilled indicator specifies whether the submitter of the reply understands the criterion as fulfilled.

Added in the model and as a property in 0.23

R3   A criterion may contain an indicator defining whether it is fulfilled or not. This indicator should be used when using the class to provide an answer. For example, economic operators use the ESPD document to provide answers to criteria defined by contracting authorities. This ESPD document contains the  the criteria classes and evidences, and this indicator is used to declare whether the economic operator fulfils each criterion.