treewide: improve template expansion

also: support *.toml as extra configuration dictionaries

image-entry.d/01-defaults.envsh

@@ -1,5 +1,13 @@
 #!/bin/sh
 
+## if IEP_DEBUG is not set, allow scripts to delete source templates
+## (they are likely not needed anymore)
+if [ "${IEP_DEBUG}" = 1 ] ; then
+	unset ENVSUBST_UNLINK_SRC J2CFG_UNLINK_SRC
+else
+	export ENVSUBST_UNLINK_SRC=1 J2CFG_UNLINK_SRC=1
+fi
+
 unset NGX_DEBUG
 NGX_DEBUG=$(/usr/sbin/angie --build-env 2>&1 | mawk '$1=="DEBUG:" {print $2;exit;}')
 NGX_DEBUG="${NGX_DEBUG:-0}"