'hipposys:filter' in a hipposys:facetrule should be an optional property

For most security domains, the hipposys:facetrule has:

hipposys:filter = false

when 'hipposys:filter' is false, it just means that the facet rule is not optional. However, in general, most of the time the 'hipposys:filter' property is false. The cnd is:

[hipposys:facetrule] > nt:base
- hipposys:facet (string) mandatory
- hipposys:value (string) mandatory
- hipposys:type (string) = 'String' mandatory < 'String', 'Name', 'Reference'
- hipposys:equals (boolean) = 'true' mandatory autocreated
- hipposys:filter (boolean) = 'false' mandatory autocreated
- hipposys:description (string)

I suggest to remove 'mandatory autocreated' and if the property is missing, just treat it as false, meaning the facet rule is not optional (there is no confusion possible if the property is not present imho but it confuses when the property is there)