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/NetworkManager/rootfs/etc/NetworkManager/system-connections/ww4-managed.ww

@@ -10,9 +10,7 @@ type={{ default "ethernet" (lower $netdev.Type) }}
 master={{ $netdev.Tags.master }}
 slave-type=bond
 {{- end }}
-{{- if $netdev.OnBoot }}
-autoconnect=true
-{{- end }}
+autoconnect={{ $netdev.OnBoot.BoolDefaultTrue }}
 
 {{- if eq (lower $netdev.Type) "bond" }}
 [bond]