* Update configuration of Caching Policy Manager to fill Last-Modified Header with modification_date.
* Web Site and Web Section are not using Caching Policy Manager
* Use getPortalWebDocumentTypeLits instead of Hardcoded portal_type
reviewed by romain

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@31901 20353a03-c40f-0410-a6d1-a30d3c3de9de