cubicweb-frbr #3774731 First implementation of the schema [validation pending]

First implementation of the schema from FRBR specifications

http://archive.ifla.org/VII/s13/frbr/frbr2.htm

prioritynormal
typebug
done in0.1.0
load0.500
load left0.000
closed by#cf3f342bc904 [schema] First implementation of the schema; closes #3774731
patch[schema] First implementation of the schema; closes #3774731 [applied]