...

• design an algorithm matching the above requirements;
• implement this algorithm and unit tests;
• test it manually using different initial assignments;

Rebalance command

New command "--rebalance" is proposed to be added.
The usage scenario is same as for "--generate" except new command is called "--rebalance".

Scenario:
1. User generates reassignment configuration by running:
--rebalance --topics-to-move-json-file topics.json --broker-list 0,1,2 --zookeeper zk:2181
2. User copies proposed reassignment configuration to reassignment.json file
3. User executes reassignment by running:
--execute --reassignment-json-file reassignment.json --zookeeper zk:2181
4. User verifies status of reassignment by running:
--verify --reassignment-json-file reassignment.json --zookeeper zk:2181

Decommission broker command

...