docker code conversions

util.sh

@@ -403,4 +403,7 @@ diagnostics() {
     systemctl status haproxy -l --no-pager | log
     logfile='octodocker_deploy.log'
     main_menu
-}
+}
+
+command_exists() { command -v "$@" > /dev/null 2>&1 }
+join_by() { local IFS="$1"; shift; echo "$*"; }