[debian] build the book with no auto-compression of book files (closes: #1906581)
Book content paths (html and rest) are now excluded from Debian compression step.
This will fix a documentation search issue on the website (doc.cubicweb.org)
Documentation build is now made optional since it can break for old distributions
and we don't want to block a new release of Cubicweb because of documentation issues.
if schema['TZDatetime'].eid is None:
add_entity_type('TZDatetime')
if schema['TZTime'].eid is None:
add_entity_type('TZTime')