Revert "configs: Update Node.js to version 20"

This reverts commit 4bae82c8.

We unfortunately still need Node 16 to compile reForis.

configs/common/node

-CONFIG_NODEJS_20=y
+CONFIG_NODEJS_16=y

patches/node/hacks/0001-Revert-node-drop-v16.x.patch

+From db618152ac7fb7686274858dad02c90270a1a303 Mon Sep 17 00:00:00 2001
+From: Michal Hrusecky <michal.hrusecky@turris.com>
+Date: Thu, 14 Dec 2023 15:41:08 +0100
+Subject: [PATCH 1/2] Revert "node: drop v16.x"
+
+This reverts commit df49d84e5f0cb861721c8baca1b0d3f7bb27e15c.
+---
+ node/Makefile | 11 +++++++++++
+ 1 file changed, 11 insertions(+)
+
+diff --git a/node/Makefile b/node/Makefile
+index 2be6614c..771da296 100644
+--- a/node/Makefile
++++ b/node/Makefile
+@@ -6,6 +6,13 @@ include $(TOPDIR)/rules.mk
+ 
+ PKG_NAME:=node
+ 
++ifeq ($(CONFIG_NODEJS_16),y)
++PKG_VERSION:=v16.20.2
++PKG_RELEASE:=2
++PKG_HASH:=576f1a03c455e491a8d132b587eb6b3b84651fc8974bb3638433dd44d22c8f49
++PATCH_DIR:=./patches/v16.x
++NODEJS_BIN_SUM:=874463523f26ed528634580247f403d200ba17a31adf2de98a7b124c6eb33d87
++else
+ ifeq ($(CONFIG_NODEJS_20),y)
+ PKG_VERSION:=v20.10.0
+ PKG_RELEASE:=1
+@@ -23,4 +30,5 @@ PATCH_DIR:=./patches/v18.x
+ endif
++endif
+ 
+ PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
+ PKG_SOURCE_URL:=https://nodejs.org/dist/$(PKG_VERSION)
+@@ -88,6 +96,9 @@ define Package/node/config
+ 		 Select node.js version.
+ 		 The host package version is also the same.
+ 
++		config NODEJS_16
++			bool "16.x End-of-Life"
++
+ 		config NODEJS_18
+ 			bool "18.x Maintenance LTS"
+ 
+-- 
+2.43.0
+