[Feature] Dump/Restore of enviFormer Models (#170)

Dump:
`./manage.py  dump_enviformer d544303c-a1ca-439d-b036-5e3413ce4a48 --output test.tar.gz`

Restore:
`./manage.py load_enviformer test.tar.gz 1062eb09-5ec7-4bdd-a8f2-ae0252eb4b06`

Co-authored-by: Tim Lorsbach <tim@lorsba.ch>
Reviewed-on: enviPath/enviPy#170

epdb/management/commands/dump_enviformer.py

@@ -0,0 +1,59 @@
+import json
+import os
+import tarfile
+from tempfile import TemporaryDirectory
+
+from django.conf import settings as s
+from django.core.management.base import BaseCommand
+from django.db import transaction
+
+from epdb.models import EnviFormer
+
+
+class Command(BaseCommand):
+    def add_arguments(self, parser):
+        parser.add_argument(
+            "model",
+            type=str,
+            help="Model UUID of the Model to Dump",
+        )
+        parser.add_argument("--output", type=str)
+
+    def package_dict_and_folder(self, dict_data, folder_path, output_path):
+        with TemporaryDirectory() as tmpdir:
+            dict_filename = os.path.join(tmpdir, "data.json")
+
+            with open(dict_filename, "w", encoding="utf-8") as f:
+                json.dump(dict_data, f, indent=2)
+
+            with tarfile.open(output_path, "w:gz") as tar:
+                tar.add(dict_filename, arcname="data.json")
+                tar.add(folder_path, arcname=os.path.basename(folder_path))
+
+            os.remove(dict_filename)
+
+    @transaction.atomic
+    def handle(self, *args, **options):
+        output = options["output"]
+
+        if os.path.exists(output):
+            raise ValueError(f"Output file {output} already exists")
+
+        model = EnviFormer.objects.get(uuid=options["model"])
+
+        data = {
+            "uuid": str(model.uuid),
+            "name": model.name,
+            "description": model.description,
+            "kv": model.kv,
+            "data_packages_uuids": [str(p.uuid) for p in model.data_packages.all()],
+            "eval_packages_uuids": [str(p.uuid) for p in model.data_packages.all()],
+            "threshold": model.threshold,
+            "eval_results": model.eval_results,
+            "multigen_eval": model.multigen_eval,
+            "model_status": model.model_status,
+        }
+
+        model_folder = os.path.join(s.MODEL_DIR, "enviformer", str(model.uuid))
+
+        self.package_dict_and_folder(data, model_folder, output)