What would you like to be added:
Change MinIO's demo to:

• use docker to deploy MinIO by default
• Layotto invoke local MinIO by default

Why is this needed:
Currently, the demo uses the MinIO official demo service by default, but the service is unstable.

For example , someone might modify some configuration, which leads to demo failure.
So we want to use docker to deploy MinIO and make the demo more stable.