Add WWbool.BoolDefaultTrue()

New support in WWbool for booleans that default "true."

Used primarily for NetDev.OnBoot.

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

overlays/wwinit/rootfs/warewulf/config.ww

@@ -7,4 +7,4 @@ WWIPMI_NETMASK="{{$.Ipmi.Netmask}}"
 WWIPMI_GATEWAY="{{$.Ipmi.Gateway}}"
 WWIPMI_USER="{{$.Ipmi.UserName}}"
 WWIPMI_PASSWORD="{{$.Ipmi.Password}}"
-WWIPMI_WRITE="{{$.Ipmi.Write}}"
+WWIPMI_WRITE="{{$.Ipmi.Write.Bool}}"