Do not add the uid schema by default to all document types definition

uid is part of the 3 schemas which are added to all document types with common and dublincore.

It has a side effect on the versioning widget which display the concatenation of uid.major and uid.minor fields (DocumentModel#getVersionLabel)

Expected behavior: uid is not a default schema, but a user can choose it among the available schemas.

Note that this behavior is a discrepency with the default definitions from the Nuxeo Platform where uid is not added to all document types, but only to those who have the Versionable facet.