First pass at a rework of the overlay subsystem in Warewulf

overlays/wwinit/etc/wicked/ifconfig/ifcfg-default.xml.ww

@@ -0,0 +1,27 @@
+<interface origin="static generated warewulf config">
+  <name>{{.NetDevs.default.Device}}</name>
+  <control>
+    <mode>boot</mode>
+  </control>
+  <firewall/>
+  <link/>
+  <ipv4>
+    <enabled>true</enabled>
+    <arp-verify>true</arp-verify>
+  </ipv4>
+  <ipv4:static>
+    <address>
+      <local>{{$.NetDevs.default.IpCIDR}}</local>
+    </address>
+    <route>
+      <nexthop>
+        <gateway>{{$.NetDevs.default.Gateway}}</gateway>
+      </nexthop>
+    </route>
+  </ipv4:static>
+  <ipv6>
+    <enabled>true</enabled>
+    <privacy>prefer-public</privacy>
+    <accept-redirects>false</accept-redirects>
+  </ipv6>
+</interface>