Add OS variant configuration

- Debian 11 has a different TFTP path than Ubuntu 18.04

Add EFI PXE boot support with conditional

- Conditionally provide different file depending on BIOS or EFI boot
  (unsupported on BSD dhcpd implementations)

Fix galaxy metadata

Change-Id: If13d18dbf0455f8e9b27054da6f0eabbb602b71f
diff --git a/vars/Debian.yml b/vars/Debian.yml
index 01b6dc6..5e02c23 100644
--- a/vars/Debian.yml
+++ b/vars/Debian.yml
@@ -13,4 +13,4 @@
 
 tftpd_service: "tftpd-hpa"
 tftpd_groupname: "tftp"
-tftpd_boot_dir: "/var/lib/tftpboot"
+tftpd_boot_dir: "/srv/tftp"
diff --git a/vars/Ubuntu_18.04.yml b/vars/Ubuntu_18.04.yml
new file mode 100644
index 0000000..35abc14
--- /dev/null
+++ b/vars/Ubuntu_18.04.yml
@@ -0,0 +1,16 @@
+---
+# dhcpd vars/Ubuntu_18.04.yml
+#
+# SPDX-FileCopyrightText: © 2020 Open Networking Foundation <support@opennetworking.org>
+# SPDX-License-Identifier: Apache-2.0
+#
+# NOTE: Only put platform/OS-specific variables in this file.
+# Put all other variables in the 'defaults/main.yml' file.
+
+dhcpd_service: "isc-dhcp-server"
+dhcpd_config_dir: "/etc/dhcp"
+dhcpd_groupname: "root"
+
+tftpd_service: "tftpd-hpa"
+tftpd_groupname: "tftp"
+tftpd_boot_dir: "/var/lib/tftpboot"