firewall: document rules for IPSec ESP/ISAKMP with 'name' option

These are recommended practices by REC-22 and REC-24 of RFC6092:
"Recommended Simple Security Capabilities in Customer Premises Equipment
(CPE) for Providing Residential IPv6 Internet Service"

Fixes FS#640

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

package/network/config/firewall/Makefile

@@ -9,7 +9,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=firewall
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(LEDE_GIT)/project/firewall3.git

package/network/config/firewall/files/firewall.config

@@ -114,6 +114,21 @@ config rule
 	option family		ipv6
 	option target		ACCEPT
 
+config rule
+	option name		Allow-IPSec-ESP
+	option src		wan
+	option dest		lan
+	option proto		esp
+	option target		ACCEPT
+
+config rule
+	option name		Allow-ISAKMP
+	option src		wan
+	option dest		lan
+	option dest_port	500
+	option proto		udp
+	option target		ACCEPT
+
 # include a file with users custom iptables rules
 config include
 	option path /etc/firewall.user
@@ -157,20 +172,6 @@ config include
 #	option dest_port	22
 #	option proto		tcp
 
-# allow IPsec/ESP and ISAKMP passthrough
-config rule
-	option src		wan
-	option dest		lan
-	option proto		esp
-	option target		ACCEPT
-
-config rule
-	option src		wan
-	option dest		lan
-	option dest_port	500
-	option proto		udp
-	option target		ACCEPT
-
 ### FULL CONFIG SECTIONS
 #config rule
 #	option src		lan