Feature: Multi-broker federated network

[pouya-eghbali]

Currently, the workers can only connect with one broker. This is sufficient to guarantee data availability; a reverse proxy with multiple brokers and a round-robin algorithm can prevent a broker from going down due to unpredicted issues. However, this arrangement is not censorship-resistant.

We need to allow users to connect to multiple brokers; the brokers must adequately talk to each other to manage the network load.