Improve sqlite test efficiency by using memory backend

Author: filippomc

infrastructure/common-images/cloudharness-django/libraries/cloudharness-django/cloudharness_django/settings.py

@@ -74,7 +74,7 @@
     DATABASE_NAME = os.path.join(getattr(settings, "PERSISTENT_ROOT", "."), f"{app_name}.sqlite3")
     DATABASE_HOST = None
     DATABASE_PORT = None
-    TEST_DATABASE_NAME = os.path.join(getattr(settings, "PERSISTENT_ROOT", "."), "testdb.sqlite3")
+    TEST_DATABASE_NAME = ":memory:"  # os.path.join(getattr(settings, "PERSISTENT_ROOT", "."), "testdb.sqlite3")
 elif current_app.harness.database.type == "postgres":
     DATABASE_ENGINE = "django.db.backends.postgresql"
     DATABASE_NAME = current_app.harness.database.postgres.initialdb