lnwire: replace instances of *btcec.PublicKey with [33]byte in ann messages

In this commit, we replace all instances of *btcec.PublicKey within the
announcement messages with a simple [33]byte. We do this as usually we
don’t need to immediately validate an announcement, therefore we can
avoid the scalar multiplications during decoding.

lnwire/node_announcement.go

@@ -7,8 +7,6 @@ import (
 	"io"
 	"net"
 	"unicode/utf8"
-
-	"github.com/roasbeef/btcd/btcec"
 )
 
 var (
@@ -59,7 +57,7 @@ type NodeAnnouncement struct {
 	Timestamp uint32
 
 	// NodeID is a public key which is used as node identification.
-	NodeID *btcec.PublicKey
+	NodeID [33]byte
 
 	// RGBColor is used to customize their node's appearance in maps and
 	// graphs