Validate bucket UUID

When the bucket UUID changes, it indicates the client isn't working with the same bucket (it's been deleted and recreated, or we're talking to a different server).

Allow specifying bucket uuid when configuring client.

if user specified non=zero bucket uuid, include bucket_uuid query param when fetching config.

The client should somehow notify the user when the bucket UUID does not match the expected value. On possibility: Modify ControlEventHandler interface to add onBucketUuidMismatch(). Client invokes it and then disconnects permanently.