server+lncfg: protocol flag to enable scid-alias, zero-conf feature bits

This allows the zero-conf and scid-alias feature bits to be toggled
using the config. The feature bits are off by default to protect users
from accidentally incurring the risk of a zero-conf channel.

server.go

@@ -530,6 +530,8 @@ func newServer(cfg *Config, listenAddrs []net.Addr,
 		NoWumbo:                  !cfg.ProtocolOptions.Wumbo(),
 		NoScriptEnforcementLease: cfg.ProtocolOptions.NoScriptEnforcementLease(),
 		NoKeysend:                !cfg.AcceptKeySend,
+		NoOptionScidAlias:        !cfg.ProtocolOptions.ScidAlias(),
+		NoZeroConf:               !cfg.ProtocolOptions.ZeroConf(),
 	})
 	if err != nil {
 		return nil, err