This introduces a new class to manage [pxe] options, which are used by the iptables PXE filter options. The configuration of [pxe] dnsmasq_interface option will be moved to the new class, following the existing implementation to configure the [dnsmasq_pxe_filter] dhcp_hostsdir option. Change-Id: If0ec9eecb70d9976de76899fc115fc9facc75fdd