Motivation:
RFC6265 specifies which characters are allowed in a cookie name and value.
Netty is currently too lax, which can used for HttpOnly escaping.
Modification:
In ServerCookieDecoder: discard cookie key-value pairs that contain invalid characters.
In ClientCookieEncoder: throw an exception when trying to encode cookies with invalid characters.
Drop old Cookie encoders and decoders that were deprecated in 4.1.
Result:
The problem described in the motivation section is fixed.