feat: integrate azure storage handling in migration pipeline

Stream transformer output to an Azure blob container when a job declares ToStorage, with per-job prefix and credential configuration.

.env.example

@@ -1,2 +1,12 @@
-PG_FROM_DB_URL=postgresql://postgres:password@localhost:5432/db
-PG_TO_DB_URL=postgresql://postgres:password@localhost:5432/db
+SOURCE_DB_URL=sqlserver://sa:password@localhost:1433?database=master&packet+size=32767&loc=UTC
+TARGET_DB_URL=postgresql://postgres:password@localhost:5432/db
+
+LOG_LEVEL=INFO
+
+AZ_STORAGE_ENABLED=false
+AZ_ACCOUNT_NAME=
+AZ_CONTAINER=
+AZ_ACCOUNT_KEY=
+AZ_USE_HTTPS=true
+AZ_SERVICE_URL=
+AZ_PREFIX=