Check feasibility with Sui event stream

[mario4tier]

Using testnet, verify that event stream can effectively be used to communicate between the network and a targeted off-chain end-point.

[mario4tier]

In particular, implement the Sui network egress and see about the latency added for getting the data out of the Sui network.

Also, figure out the best way to store the data such that it can be deleted eventually (immutable feels wrong for encrypted data that will never have any purpose in the future).