[web/request] don't play tricks with utc offset
We need an UTC datetime from a time.time()-type value. It turns out
datetime provides a method to do just that. Related to #2154655.
Document: cubicweb-doc
Title: CubicWeb documentation
Author: Logilab
Abstract: Some base documentation for CubicWeb users and developpers
Section: Apps/Programming
Format: HTML
Index: /usr/share/doc/cubicweb-documentation/index.html
Files: /usr/share/doc/cubicweb-documentation/*.html