Add skeleton for module and userspace iptables management

Special thanks to https://github.com/drivenets/iptables_extensions
repository with detailed explanations of iptables userspace interaction
with the kernel module.

libipt_YTUNBLOCK.c

@@ -0,0 +1,26 @@
+// Used to register target in iptables
+#include <stdio.h>
+#include <xtables.h>
+
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include "ipt_YTUNBLOCK.h"
+
+#define _init __attribute__((constructor)) _INIT
+#define __maybe_unused __attribute__((__unused__))
+
+static void YTKB_help(void) {
+	printf("Youtube Unblock - bypass youtube slowdown DPI in Russia\n");
+}
+
+static struct xtables_target ykb_tg_reg = {
+	.name           = "YTUNBLOCK",
+	.version        = XTABLES_VERSION,
+	.family         = NFPROTO_IPV4,
+	.size           = XT_ALIGN(sizeof(struct xt_ytunblock_tginfo)),
+	.userspacesize  = XT_ALIGN(sizeof(struct xt_ytunblock_tginfo)),
+	.help           = YTKB_help,
+};
+
+void _init(void) {
+    xtables_register_target(&ykb_tg_reg);
+}