The maximum number of incoming streams doesn't need to be negotiated. It
is a value that is only announced by the peer, and has to be respected.
Furthermore, Chrome doesn't seem to care about the MSPC value anymore
(since MIDS was introduced), so there's no need to send this in the
handshake any more.
The params negotiator was just keeping track of the value set in the
quic.Config. The max flow control increments are not subject to
negotiation, but an independent implementation decision of every peer.
The idle timeout doesn't need to be negotiated, simply announcing it to
the peer is sufficient. We now close the session if there's no incoming
network activity for the duration of the local idle timeout, and we
send a PING frame after half the remote idle timeout (if keep alives are
enabled).
