This commit adds support for the "SameSite" attribute in response
cookies. As explained in rfc6265bis, this attribute can be used to limit
the scope of a cookie so that it can't be attached to a request unless
it is sent from the "same-site".
This feature is currently supported by Google Chrome and Firefox, other
browsers will ignore this attribute.
This feature can help prevent CSRF attacks; this is why this commit adds
this attribute by default for SESSION Cookies in WebFlux.
See: https://tools.ietf.org/html/draft-ietf-httpbis-rfc6265bis
Issue: SPR-16418
09d9450154