Improve JSF / DocumentModel binding

The binding inside JSF should be more simple.

The ActionListeners should not contains any mapping / casting logic.
Typically, the mapping from FileUpload to nx:content should not be made at ActionListener level : this should be handled at URLResolverlevel (like Dates) or in a dedicated phase listener. The transformation logic should be registred using an extension point at web document declaration level : ie, each document can declare it's own mapping model.

The differents facets of the document (versions, relations, wf ...) should be directly accessible via the document model.
Instead of using separated Seam context variables (one for versioninfo, one for relations infos ...), all informations generated by the services should be bound to facets of the document model.
currentItem.getFacet(VERSON) => VersionInfo
currentItem.getFacet(RELATIONS) => RelationsInfo

Theses facets should be easily accesibled to the facelets using the custom url resolver : currentItem@@RelationInfo.linkedDocuments