[IMP] portal: add a generic PortalSidebar widget to be used in customer portal

 with this commit, this generic widget allow to basic functionality for portal sidebar like: print btn (direclty print the document),
 set due or delay label of the document (based on given date), used affix to locked to an area on the page for sidebar.
 Purpose is to reuse it in account customer portal and online quotes notably.
 some css code convert to the less file to have working portal sidebar skeleton, which is already used in website_quote

 Task ID: 39876