Fix newline handling in file, softlink, and ImportLink template functions

Use state-based routing instead of sentinel strings, so whitespace-trimming
syntax (e.g. `{{- file "name" -}}`) correctly creates all named files and
symlinks.

Fixes: #2118

Signed-off-by: Jonathon Anderson <janderson@ciq.com>
Co-authored-by: Christian Goll <cgoll@suse.com>
Signed-off-by: Jonathon Anderson <janderson@ciq.com>

overlays/ifcfg/rootfs/etc/sysconfig/network-scripts/ifcfg.ww

@@ -1,5 +1,5 @@
 {{- range $devname, $netdev := .NetDevs }}
-{{ file (print "ifcfg-" $devname ".conf") }}
+{{- file (print "ifcfg-" $devname ".conf") -}}
 # This file is autogenerated by warewulf
 {{- if eq $netdev.Type "vlan" }}
 VLAN=yes

overlays/ifcfg/rootfs/etc/sysconfig/network-scripts/route.ww

@@ -1,5 +1,5 @@
 {{- range $devname, $netdev := .NetDevs }}
-{{ file (print "route-" $devname ".conf") }}
+{{- file (print "route-" $devname ".conf") -}}
 # This file is autogenerated by warewulf
 {{- range $tk, $tv := $netdev.Tags }}
 {{- if eq (substr 0 5 $tk) "route" }}