Add ZFSBootMenu and a check if initrd is present

Closes: https://github.com/netbootxyz/netboot.xyz/issues/1469

roles/netbootxyz/defaults/main.yml

@@ -714,6 +714,11 @@ utilitiesefi:
     enabled: true
     name: System Rescue CD
     type: ipxemenu
+  zfsbootmenu:
+    enabled: true
+    kernel: ${live_endpoint}{{ endpoints.zfsbootmenu.path }}zfsbootmenu-recovery-x86_64.efi 
+    name: ZFSBootMenu
+    type: direct
 utilitiespcbios32:
   clonezilla:
     enabled: true

roles/netbootxyz/templates/menu/utils-efi.ipxe.j2

@@ -24,7 +24,9 @@ goto utils_exit
 :{{ key }}
 imgfree
 kernel {{ value.kernel }}
+{% if value.initrd is defined and value.initrd %}
 initrd {{ value.initrd }}
+{% endif %}
 boot
 goto utils_exit
 {% endif %}