Update network interface bonding configuration and documentation

- Closes: #1482
- Closes: #1280

This also corrects poor handling of whitespace around the "file" function
throughout the templates, given experiences with the network templates while
implementing the bond behavior. Since the file function actually does produce
output (that is parsed by Warewulf itself) it should not collaps prefix
whitespace.

Signed-off-by: Jonathon Anderson <janderson@ciq.com>

overlays/debian.interfaces/internal/debian_interfaces_test.go

@@ -52,6 +52,7 @@ func Test_wickedOverlay(t *testing.T) {
 const debian_interfaces string = `backupFile: true
 writeFile: true
 Filename: default
+
 # This file is autogenerated by warewulf
 allow-hotplug wwnet0
 iface wwnet0 inet static
@@ -59,6 +60,7 @@ iface wwnet0 inet static
   netmask 255.255.255.0
   gateway 192.168.3.1
   mtu 1500
+
 backupFile: true
 writeFile: true
 Filename: secondary

overlays/debian.interfaces/rootfs/etc/network/interfaces.d/default.ww

@@ -1,5 +1,5 @@
 {{- range $devname, $netdev := .ThisNode.NetDevs }}
-{{- file $devname }}
+{{ file $devname }}
 # This file is autogenerated by warewulf
 {{- if $netdev.OnBoot }}
 auto {{ $netdev.Device }}