Revert "dnsmasq: drop dhcp-proxy option"

This reverts commit 554bf1f711.

Turns out ISC dhcrelay will relay even unicast packets from clients. So
the DHCP server got both the routed and the relayed query.

This tells dnsmasq to tell clients to send everything through the relay.
Since everything now comes from the relay we can drop access from client
networks.

roles/dnsmasq/tasks/main.yml

@@ -38,10 +38,4 @@
   - 10-ranges.conf
   notify: restart dnsmasq
 
-- name: Configure nftables
-  template:
-    dest: '/etc/nftables.d/dnsmasq.nft'
-    src: 'dnsmasq.nft.j2'
-  notify: reload nftables
-
 # TODO netboot config