Add Constraints (Auflagen) to PlantProtectionProduct

[montanajava]

Usage constraints or restrictions are very valuable to know when, for instance, applying phytosanitary or plant protection product on a field. Such constraints, are, however, fully free text and are not parseable.

Constraints, or Restrictions (de=Auflage) should be machine-parsable and added as a 0-n attribute to a plant protection product.

The description of how that looks should flow from infoPhyto.

[montanajava]

Auflagen come from infoPhyto and are currently described in freetext format. These should be parseable.

Examples: Can not be used within 10 metres from water.