initramfs: T1971: Added initramfs-hook script for including modules

The script allows include to initramfs or include and force to load any modules, listed inside.
Initially, the script replaces the trick used for intel drivers

data/live-build-config/includes.chroot/etc/initramfs-tools/hooks/10-vyos-add-modules

@@ -0,0 +1,23 @@
+#!/bin/sh
+PREREQ=""
+prereqs()
+{
+    echo "$PREREQ"
+}
+case $1 in
+prereqs)
+    prereqs
+    exit 0
+    ;;
+esac
+. /usr/share/initramfs-tools/hook-functions
+# Begin real processing below this line
+
+# include listed modules to initramfs but not load them without the necessity
+manual_add_modules igb ixgbe ixgbevf i40e i40evf
+
+# include modules from file (one per line) to initramfs but not load them without the necessity
+# add_modules_from_file /tmp/modlist
+
+# include listed modules to initramfs and load them during the boot
+# force_load xxx