Add ObjectStore source

.env.example

@@ -0,0 +1,9 @@
+# Copy to .env and replace both empty values with random credentials.
+# The Compose file refuses to start without them.
+S3_ACCESS_KEY=
+S3_SECRET_KEY=
+S3_BUCKET=objects
+S3_REGION=us-east-1
+HOST_PORT=9000
+MAX_OBJECT_BYTES=10485760
+MAX_TOTAL_BYTES=2147483648