Run integration tests via custom action (#929)

This PR unifies integration testing infra

Author: nfx

.codegen.json

@@ -3,8 +3,15 @@
     "src/databricks/labs/ucx/__about__.py": "__version__ = \"$VERSION\""
   },
   "toolchain": {
-    "required": ["hatch"],
-    "pre_setup": ["hatch env create"],
-    "prepend_path": ".venv/bin"
+    "required": ["python3"],
+    "pre_setup": [
+      "python3 -m pip install hatch==1.7.0",
+      "python3 -m hatch env create"
+    ],
+    "prepend_path": ".venv/bin",
+    "acceptance_path": "tests/integration",
+    "test": [
+      "pytest -n 4 --cov src --cov-report=xml --timeout 30 tests/unit --durations 20"
+    ]
   }
 }