[web] stop looking at a request's Cache-Control header
As per RFC 7234 (HTTP 1.1 Caching):
The "Cache-Control" header field is used to specify directives for
caches along the request/response chain.
CubicWeb is not a cache.
Add some entities
-----------------
As manager, you can access to entity creation forms by using the `site management`_ page.
.. _`site management`: ../manage
As regular user, the index page or the action box may propose some links to create entities according to the context.