conceptualize attribute for "castration" in v2

[hurni]

the ÖK has shown the need to add castration as an attribute to an animal. Proposed was that "castration" should be added to the enumeration of "biologicalSexType". This does not seem correct, as castration is no sexType. Furthermore "biologicalSexType" should rather be simplified to only contain sex instead of mirroring businessLogic , e.g. value <"M_OR_F"> for "Männlich oder weiblich: In einigen Listen sind Tiere aufgeführt, die entweder weiblich oder männlich sein können.", <"NA"> and <"undefined">.

proposition to be discussed in AG Nutztiere: new element in sequence of
<xs:complexType name="individualAnimalType"><xs:element name="reproductivionCapability" type="xs:boolean" minOccurs="0">xs:annotation<xs:documentation xml:lang="en">Is the animal capable to reproduce?</xs:documentation></xs:annotation>

[hurni]

perhaps also required for animalGroup?