Java: Add model generator script that emits data extensions.

java/ql/src/utils/model-generator/GenerateFlowModelExtensions.py

@@ -0,0 +1,15 @@
+#!/usr/bin/python3
+
+import sys
+import os.path
+import subprocess
+
+# Add Model as Data script directory to sys.path.
+gitroot = subprocess.check_output(["git", "rev-parse", "--show-toplevel"]).decode("utf-8").strip()
+madpath = os.path.join(gitroot, "misc/scripts/models-as-data/")
+sys.path.append(madpath)
+
+import generate_flow_model_extensions as model
+
+language = "java"
+model.Generator.make(language).run()