wgengine/wgcfg: plumb down audit log IDs (#5855)

The node and domain audit log IDs are provided in the map response,
but are ultimately going to be used in wgengine since
that's the layer that manages the tstun.Wrapper.

Do the plumbing work to get this field passed down the stack.

Signed-off-by: Joe Tsai <joetsai@digital-static.net>

wgengine/wgcfg/config.go

@@ -8,6 +8,7 @@ package wgcfg
 import (
 	"net/netip"
 
+	"tailscale.com/logtail"
 	"tailscale.com/types/key"
 )
 
@@ -22,6 +23,13 @@ type Config struct {
 	MTU        uint16
 	DNS        []netip.Addr
 	Peers      []Peer
+
+	// NetworkLogging enables network logging.
+	// It is disabled if either ID is the zero value.
+	NetworkLogging struct {
+		NodeID   logtail.PrivateID
+		DomainID logtail.PrivateID
+	}
 }
 
 type Peer struct {