[#454] adopt enforcement framework + STATUS; modernize librenms agent scripts

check-rules green; shellcheck fixes to dpkg.sh/os-updates.sh (legacy
backticks, unquoted vars, array-quoted command builders); Discourse
pointers added to basis docs; awx/k8s/compliance repos referenced.
https://projects.knownelement.com/issues/454

roles/oam/files/librenms/dpkg.sh

@@ -5,18 +5,22 @@
 if [ -x /usr/bin/dpkg-query ]; then
   DATE=$(date +%s)
   FILE=/var/cache/librenms/agent-local-dpkg
-  
+
   [ -d /var/cache/librenms ] || mkdir -p /var/cache/librenms
-  
-  if [ ! -e $FILE ]; then
-    dpkg-query -W --showformat='${Status} ${Package} ${Version} ${Architecture} ${Installed-Size}\n'|grep " installed "|cut -d\  -f4- > $FILE
+
+  refresh() {
+    dpkg-query -W --showformat='${Status} ${Package} ${Version} ${Architecture} ${Installed-Size}\n' \
+      | grep " installed " | cut -d\  -f4- > "$FILE"
+  }
+
+  if [ ! -e "$FILE" ]; then
+    refresh
   fi
-  FILEMTIME=$(stat -c %Y $FILE)
-  FILEAGE=$(($DATE-$FILEMTIME))
-  if [ $FILEAGE -gt 1800 ]; then
-    dpkg-query -W --showformat='${Status} ${Package} ${Version} ${Architecture} ${Installed-Size}\n'|grep " installed "|cut -d\  -f4- > $FILE
+  FILEMTIME=$(stat -c %Y "$FILE")
+  FILEAGE=$((DATE - FILEMTIME))
+  if [ "$FILEAGE" -gt 1800 ]; then
+    refresh
   fi
   echo "<<<dpkg>>>"
-  cat $FILE
+  cat "$FILE"
 fi
-