move the max flow control increments out of the params negotiator

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.

internal/handshake/interface.go

@@ -28,8 +28,6 @@ type CryptoSetup interface {
 
 // TransportParameters are parameters sent to the peer during the handshake
 type TransportParameters struct {
-	RequestConnectionIDOmission           bool
-	MaxReceiveStreamFlowControlWindow     protocol.ByteCount
-	MaxReceiveConnectionFlowControlWindow protocol.ByteCount
-	IdleTimeout                           time.Duration
+	RequestConnectionIDOmission bool
+	IdleTimeout                 time.Duration
 }