Run without cookies

[g105b]

When there isn't any need for 'em, don't set 'em.

[g105b]

This should be possible now the Service Container has moved to lazy initialisation - there doesn't need to be a call to session_start() if there is no use of the session from the page logic. Just needs a test case put in place.

[g105b]

To clarify a common use case, the only time a cookie is required is whenever a POST form is on the page. For typical brochure sites, this is only going to be on the contact page or similar, so the question is, should a cookie only be set on the URL path it's used on, or is this overkill?