feat: add support for file upload and return as file in async endpoints (#152)

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

docling_serve/storage.py

@@ -0,0 +1,16 @@
+import tempfile
+from functools import lru_cache
+from pathlib import Path
+
+from docling_serve.settings import docling_serve_settings
+
+
+@lru_cache
+def get_scratch() -> Path:
+    scratch_dir = (
+        docling_serve_settings.scratch_path
+        if docling_serve_settings.scratch_path is not None
+        else Path(tempfile.mkdtemp(prefix="docling_"))
+    )
+    scratch_dir.mkdir(exist_ok=True, parents=True)
+    return scratch_dir