add script url and path support

README.md

@@ -156,7 +156,12 @@ The script step will execute a script.
 "steps": [
   {
     "type": "script",
+    // use path for local scripts
     "path": "/global/install-docker.sh" // local path (here: resources/scripts/install-docker.sh)
+    // or use url for remote scripts
+    "url": "https://xyz.abc/scripts/install-docker.sh" // remote url
+    // or use lxc_path for scripts inside the lxc
+    "lxc_path": "/root/install-docker.sh" // lxc path
   }
 ]
 ```